Examples with solutions for Variables and Algebraic Expressions: Common denominators with variables

Exercise #1

14a+13x+24a+18+38=? \frac{1}{4}a+\frac{1}{3}x+\frac{2}{4}a+\frac{1}{8}+\frac{3}{8}=\text{?}

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Combine like terms.
  • Step 2: Simplify the expression.

Now, let's work through each step:
Step 1: Start by identifying and combining like terms in the expression 14a+13x+24a+18+38\frac{1}{4}a + \frac{1}{3}x + \frac{2}{4}a + \frac{1}{8} + \frac{3}{8}. Recognize that 14a\frac{1}{4}a and 24a\frac{2}{4}a are like terms since they both involve the variable aa.

Combine these terms:

14a+24a=34a\frac{1}{4}a + \frac{2}{4}a = \frac{3}{4}a

Step 2: Look at the constant terms 18+38\frac{1}{8} + \frac{3}{8}. Since these fractions have a common denominator, add them directly:

18+38=48=12\frac{1}{8} + \frac{3}{8} = \frac{4}{8} = \frac{1}{2}

Combine all the terms together to form the simplified expression:

34a+13x+12\frac{3}{4}a + \frac{1}{3}x + \frac{1}{2}

Therefore, the solution to the problem is 34a+13x+12 \frac{3}{4}a + \frac{1}{3}x + \frac{1}{2} .

Answer

34a+13x+12 \frac{3}{4}a+\frac{1}{3}x+\frac{1}{2}

Exercise #2

34+18m+28n+178m=? \frac{3}{4}+\frac{1}{8}m+\frac{2}{8}n+\frac{17}{8}m=\text{?}

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Simplify the expression by combining like terms and simplifying fractions.
  • Step 2: Analyze coefficients of like terms and reduce them to simplest form.
  • Step 3: Choose the correct multiple-choice option as the final answer.

Now, let's work through each step:
Step 1: The expression is 34+18m+28n+178m \frac{3}{4}+\frac{1}{8}m+\frac{2}{8}n+\frac{17}{8}m . We identify like terms and consider the fraction denominators.

Step 2: Combine the terms involving m m :

18m+178m=1+178m=188m \frac{1}{8}m + \frac{17}{8}m = \frac{1+17}{8}m = \frac{18}{8}m .

We simplify 188\frac{18}{8} to 94\frac{9}{4}. Therefore, this becomes 94m \frac{9}{4}m .

Step 3: Include the other terms that cannot be further simplified as they are alone. Thus, the entire expression becomes:

34+94m+14n \frac{3}{4} + \frac{9}{4}m + \frac{1}{4}n .

This can be rearranged to 34+214m+14n \frac{3}{4} + 2\frac{1}{4}m + \frac{1}{4}n , where each part is shown in terms of mixed numbers for clearer expression matching.

Therefore, the solution to the problem is 34+214m+14n \frac{3}{4}+2\frac{1}{4}m+\frac{1}{4}n .

Answer

34+214m+14n \frac{3}{4}+2\frac{1}{4}m+\frac{1}{4}n

Exercise #3

x8+318+x4+14x+y8=? \frac{x}{8}+\frac{31}{8}+\frac{x}{4}+\frac{1}{4}x+\frac{y}{8}=\text{?}

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Make sure all terms have a common denominator.
  • Step 2: Combine like terms.
  • Step 3: Simplify the algebraic expression.

Now, let's work through each step:
Step 1: Convert all terms to have a common denominator. The common denominator for 4 and 8 is 8. Thus:
- x4 \frac{x}{4} becomes 2x8 \frac{2x}{8} when converted to have the denominator 8,
- 14x \frac{1}{4}x also becomes 2x8 \frac{2x}{8} when converted to 8.

Step 2: Combine the like terms.
- Combine the x x terms: x8+2x8+2x8=5x8 \frac{x}{8} + \frac{2x}{8} + \frac{2x}{8} = \frac{5x}{8} .
- The constant term: 318 \frac{31}{8} .
- The term with y y : y8 \frac{y}{8} .

Step 3: Write the final expression:

The simplified expression is 318+5x8+y8 \frac{31}{8} + \frac{5x}{8} + \frac{y}{8} .

Therefore, combining it we have 378+58x+y8 3\frac{7}{8}+\frac{5}{8}x+\frac{y}{8} . This matches the given choice 378+58x+y8 3\frac{7}{8}+\frac{5}{8}x+\frac{y}{8} .

Hence, the solution to the problem is 378+58x+y8 3\frac{7}{8}+\frac{5}{8}x+\frac{y}{8} .

Answer

378+58x+y8 3\frac{7}{8}+\frac{5}{8}x+\frac{y}{8}

Exercise #4

38a+149b+119b+68a=? \frac{3}{8}a+\frac{14}{9}b+1\frac{1}{9}b+\frac{6}{8}a=\text{?}

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Group and simplify terms with the same variable.
  • Step 2: Convert any mixed numbers to improper fractions.
  • Step 3: Find a common denominator to combine fractions.
  • Step 4: Simplify the expression.

Let's work through the steps:
Step 1: Start by grouping like terms. The expression is:
38a+68a+149b+119b \frac{3}{8}a + \frac{6}{8}a + \frac{14}{9}b + 1\frac{1}{9}b .
Step 2: Convert the mixed number to an improper fraction. For 119b 1\frac{1}{9}b : 119b=109b 1\frac{1}{9}b = \frac{10}{9}b .
Rewrite the expression: 38a+68a+149b+109b \frac{3}{8}a + \frac{6}{8}a + \frac{14}{9}b + \frac{10}{9}b .
Step 3: Combine the a a -terms and b b -terms separately:
The a a -terms: 38a+68a=(38+68)a=98a \frac{3}{8}a + \frac{6}{8}a = \left(\frac{3}{8} + \frac{6}{8}\right)a = \frac{9}{8}a .
For the b b -terms: 149b+109b=(149+109)b=249b \frac{14}{9}b + \frac{10}{9}b = \left(\frac{14}{9} + \frac{10}{9}\right)b = \frac{24}{9}b .
Simplify 249 \frac{24}{9}: 249=83 \frac{24}{9} = \frac{8}{3} after dividing by the greatest common divisor 3.
Step 4: Combine simplified terms: 98a+83b \frac{9}{8}a + \frac{8}{3}b .
Convert 98a \frac{9}{8}a to a mixed number: 98a=118a \frac{9}{8}a = 1\frac{1}{8}a .
Convert 83b \frac{8}{3}b to a mixed number: 83b=223b \frac{8}{3}b = 2\frac{2}{3}b .
Thus, the simplified expression is: 118a+223b 1\frac{1}{8}a + 2\frac{2}{3}b .

Therefore, the solution to the problem is 118a+223b 1\frac{1}{8}a + 2\frac{2}{3}b .

Answer

118a+223b 1\frac{1}{8}a+2\frac{2}{3}b

Exercise #5

14a+12a+x3+43b+23x=? \frac{1}{4a}+\frac{1}{2a}+\frac{x}{3}+\frac{4}{3}b+\frac{2}{3}x=\text{?}

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Simplify and combine fractions with a a .
  • Step 2: Simplify and combine terms with x x .
  • Step 3: Express the final simplified algebraic expression.

Now, let's work through each step:
Step 1: Look at the terms with a a : 14a+12a \frac{1}{4a} + \frac{1}{2a} .
Find a common denominator, which is 4 4 in this case:

14a+24a=1+24a=34a \frac{1}{4a} + \frac{2}{4a} = \frac{1 + 2}{4a} = \frac{3}{4a} .

Step 2: Simplify and combine terms with x x :

x3+23x=1x3+2x3=3x3=x \frac{x}{3} + \frac{2}{3}x = \frac{1x}{3} + \frac{2x}{3} = \frac{3x}{3} = x .

Step 3: Combine all terms together in the expression. Keep the b b -related term as it is and combine:

34a+x+43b \frac{3}{4a} + x + \frac{4}{3}b .

Therefore, the solution to the problem is 34a+x+43b \frac{3}{4a} + x + \frac{4}{3}b , which matches choice 2.

Answer

34a+x+43b \frac{3}{4a}+x+\frac{4}{3}b