Question

Here is a linear equation in two variables: 2x+4y−31=123. Solve the equation, first for x and then for y.

Answer 1

Answer:

$x = 77 - 2y$

$y = \frac{77 - x}{2}$

Step-by-step explanation:

Given

$2x + 4y - 31 = 123$

Required

Solve for x and for y

$2x + 4y - 31 = 123$

Add 31 to both sides

$2x + 4y - 31+31 = 123+31$

$2x + 4y = 154$

Solving for x

Subtract 4y from both sides

$2x + 4y - 4y = 154 - 4y$

$2x = 154 - 4y$

Divide by 2

$x = 77 - 2y$

Solving for y

$2x + 4y = 154$

Subtract 2x from both sides

$2x - 2x + 4y = 154 - 2x$

$4y = 154 - 2x$

Divide by 4

$y = \frac{154 - 2x}{4}$

Split

$y = \frac{77 - x}{2}$