Chapter 3: Q9. (page 133)

Describe and correct the error in solving the equation
4x + 7 = x – 2

Short Answer

Expert verified

The error is in first step where the sum of x and $- 4 x$ is written as $3 x$ instead of $- 3 x$ .

The correct solution of the equation will be $x = - 3$

Step by step solution

Step-1 – Given

The given equation is $4 x + 7 = x - 2$ .

Step-2 – To determine

We have to describe and correct the error..

Step-3 – Calculation

The provided solution of the equation is:

$\begin{array}{l} 4 x + 7 = x - 2 \\ 4 x + 7 - 4 x = x - 2 - 4 x \\ 7 = 3 x - 2 \\ 7 + 2 = 3 x - 2 + 2 \\ 9 = 3 x \\ 3 = x \end{array}$

From, the given solution, we see that the error occurred in first step where the sum of x and $- 4 x$ is written as $3 x$ instead of $- 3 x$ .

The solution can be obtained correctly as:

$\begin{array}{l} 4 x + 7 = x - 2 writetheoriginalequation \\ 4 x - x + 7 = x - x - 2 subtract x frombothsides \\ 3 x + 7 = 0 - 2 simplify \\ 3 x + 7 - 7 = - 2 - 7 subtract7frombothsides \\ 3x = - 9 simplify \\ \frac{3 x}{3} = \frac{- 9}{3} divideeachby3 \\ x = - 3 simplify \end{array}$

So, the correct solution of the equation is $x = - 3$

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Describe and correct the error in solving the equation
4x + 7 = x – 2

Short Answer

Step by step solution

Step-1 – Given

Step-2 – To determine

Step-3 – Calculation

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Describe and correct the error in solving the equation4x + 7 = x – 2

Short Answer

Step by step solution

Step-1 – Given

Step-2 – To determine

Step-3 – Calculation

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Math Textbooks

Geometry

Theoretical and Mathematical Physics

Pure Maths

Calculus

Applied Mathematics

Discrete Mathematics

Study anywhere. Anytime. Across all devices.

Describe and correct the error in solving the equation
4x + 7 = x – 2