Solve for X: -25-42÷x+18×2÷4=-23 Order of Operations Challenge

Order of Operations with Division Variables

How much is x equal to?

2542 ⁣:x+18×2 ⁣:4=23 -25-42\colon x+18\times2\colon4=-23

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:00 Solve the following problem
00:03 Solve according to the correct order of operations, one operation at a time
00:07 Write the division as a fraction
00:11 Solve the multiplication and division before addition and subtraction
00:33 Isolate the unknown X
00:46 Solve from left to right
01:05 Multiply by X to eliminate it from the denominator
01:12 Isolate the unknown X
01:20 This is the solution

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

How much is x equal to?

2542 ⁣:x+18×2 ⁣:4=23 -25-42\colon x+18\times2\colon4=-23

2

Step-by-step solution

We begin by placing the multiplication exercise inside of parentheses:

2542 ⁣:x+(18×2) ⁣:4=23 -25-42\colon x+(18\times2)\colon4=-23

2542 ⁣:x+36 ⁣:4=23 -25-42\colon x+36\colon4=-23

We will then place the division exercise inside of parentheses:

2542 ⁣:x+(36 ⁣:4)=23 -25-42\colon x+(36\colon4)=-23

2542 ⁣:x+9=23 -25-42\colon x+9=-23

Next we rearrange the exercise in order to simplify it:

25+942 ⁣:x=23 -25+9-42\colon x=-23

(25+9)42 ⁣:x=23 (-25+9)-42\colon x=-23

We then solve the exercise inside of the parenthesis and obtain the following:

1642 ⁣:x=23 -16-42\colon x=-23

We rearrange the fractions and obtain the following:

42 ⁣:x=23+16 -42\colon x=-23+16

42 ⁣:x=7 -42\colon x=-7

We multiply by x and obtain the following:

42=7x -42=-7x

Lastly we divide by negative 7:

x=427=6 x=\frac{-42}{-7}=6

3

Final Answer

6

Key Points to Remember

Essential concepts to master this topic
  • PEMDAS Rule: Multiplication and division before addition and subtraction
  • Technique: Calculate 18×2÷4=36÷4=9 18\times2\div4 = 36\div4 = 9 first
  • Check: Substitute x = 6: 2542÷6+9=257+9=23 -25-42\div6+9 = -25-7+9 = -23

Common Mistakes

Avoid these frequent errors
  • Solving left to right without following order of operations
    Don't calculate -25-42÷x first = wrong sequence! This ignores PEMDAS and gives incorrect intermediate values. Always handle multiplication and division before addition and subtraction.

Practice Quiz

Test your knowledge with interactive questions

\( 100+5-100+5 \)

FAQ

Everything you need to know about this question

Why do I calculate 18×2÷4 before dealing with -25?

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Order of operations (PEMDAS) requires multiplication and division first! You must simplify 18×2÷4=9 18\times2\div4 = 9 before adding or subtracting other terms.

Can I move -42÷x to the other side first?

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Not directly! You need to simplify all terms first using order of operations. After getting 2542÷x+9=23 -25-42\div x+9=-23 , then you can rearrange terms algebraically.

How do I isolate x when it's in the denominator?

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First isolate the fraction: 42÷x=7 -42\div x = -7 . Then multiply both sides by x to get 42=7x -42 = -7x , and finally divide by -7.

What if I get a negative answer for x?

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Check your arithmetic! In this problem, x=427=6 x = \frac{-42}{-7} = 6 because negative divided by negative equals positive. Always verify by substituting back.

Why does the explanation rearrange terms like -25+9?

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Rearranging helps combine like terms more easily! Moving 25+9=16 -25+9 = -16 together simplifies the equation before isolating the variable term.

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