Solve (9+17x)×(6+1)=420: Find the Value of X

Linear Equations with Order of Operations

(9+17x)×(6+1)=420 (9+17x)\times(6+1)=420

Calculate a X

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:00 Find X
00:03 Make sure to open parentheses properly
00:07 Each term in parentheses multiplies each term in the second parentheses
00:25 Solve each multiplication and then sum
00:50 Collect like terms
01:00 Isolate X
01:31 And this is the solution to the question

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

(9+17x)×(6+1)=420 (9+17x)\times(6+1)=420

Calculate a X

2

Step-by-step solution

We begin by solving the addition exercise in the right parenthesis:

(9+17x)×7=420 (9+17x)\times7=420

We then multiply each of the terms inside the parentheses by 7:

(9×7)+(17x×7)=420 (9\times7)+(17x\times7)=420

We continue by solving each of the exercises inside of the parentheses:

63+119x=420 63+119x=420

Following this we rearrange the sections whilst maintaining the appropriate sign:

119x=42063 119x=420-63

119x=357 119x=357

Finally we divide the two parts by 119:

119119x=357119 \frac{119}{119}x=\frac{357}{119}

x=3 x=3

3

Final Answer

3

Key Points to Remember

Essential concepts to master this topic
  • Order of Operations: Simplify parentheses first, then multiply or divide
  • Distribution: Multiply 7 by each term: 7×9=63 7 \times 9 = 63 and 7×17x=119x 7 \times 17x = 119x
  • Verification: Check by substituting x = 3: (9+51)×7=60×7=420 (9+51) \times 7 = 60 \times 7 = 420

Common Mistakes

Avoid these frequent errors
  • Ignoring order of operations
    Don't solve the multiplication first and ignore the addition in parentheses = wrong setup! This breaks the fundamental rule that parentheses come before multiplication. Always simplify what's inside parentheses first, then multiply.

Practice Quiz

Test your knowledge with interactive questions

It is possible to use the distributive property to simplify the expression below?

What is its simplified form?

\( (ab)(c d) \)

\( \)

FAQ

Everything you need to know about this question

Why do I need to solve (6+1) first?

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The order of operations (PEMDAS) says parentheses come first! You must calculate 6+1=7 6+1=7 before multiplying by the other expression.

Can I distribute the multiplication before simplifying the parentheses?

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Technically yes, but it's much harder! You'd have to distribute (9+17x) (9+17x) to both 6 and 1 separately. It's easier to simplify (6+1)=7 (6+1)=7 first.

How do I know when to move terms to the other side?

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Move terms to isolate the variable! When you have 63+119x=420 63+119x=420 , subtract 63 from both sides to get 119x=357 119x=357 .

What if I get a decimal answer instead of 3?

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Check your arithmetic! Common errors include forgetting to simplify (6+1) (6+1) or making calculation mistakes with 42063=357 420-63=357 or 357÷119=3 357÷119=3 .

How can I check if x = 3 is correct?

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Substitute back into the original equation: (9+17×3)×(6+1)=(9+51)×7=60×7=420 (9+17 \times 3) \times (6+1) = (9+51) \times 7 = 60 \times 7 = 420

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