Question

A. Find and explain the error made.

B. Fix it by showing the correct solution.
3x - 4 = 7x + 12
-4 = 4x + 12
8 = 4x
X = 2

Answer 1

Answer: x= -4

Explanation:

3x + -4 = 7x + 12

Reorder the terms:

-4 + 3x = 7x + 12

Reorder the terms:

-4 + 3x = 12 + 7x

Solving

-4 + 3x = 12 + 7x

Solving for variable 'x'.

Move all terms containing x to the left... all other terms to the right.

Add '-7x' to each side of the equation.

-4 + 3x + -7x = 12 + 7x + -7x

Combine like terms: 3x + -7x = -4x

-4 + -4x = 12 + 7x + -7x

Combine like terms: 7x + -7x = 0

-4 + -4x = 12 + 0

-4 + -4x = 12

Add '4' to each side of the equation.

-4 + 4 + -4x = 12 + 4

Combine like terms: -4 + 4 = 0

0 + -4x = 12 + 4

-4x = 12 + 4

Combine like terms: 12 + 4 = 16

-4x = 16

Divide each side by '-4'.

x = -4

Simplifying

x = -4