Solve the equation by substitution method (y-1/4x=3,3y+x=23)

2 answers

yes
y - 1 / 4 x = 3

3 y + x = 23

First equation:

y - 1 / 4 x = 3

Add 1 / 4 x to both sides

y = 3 + 1 / 4 x

Substitute y with 3 + 1 / 4 x in the second equation

3 y + x = 23

3 ( 3 + 1 / 4 x ) + x = 23

9 + 3 / 4 x + x = 23

9 + 3 / 4 x + 4 / 4 x = 23

9 + 7 / 4 x = 23

Subtract 9 to both sides

7 / 4 x = 14

Multiply both sides by 4

7 x = 56

Divide both sides by 7

x = 8

Substitute x with 8 in the first equation

y - 1 / 4 x = 3

y - 1 / 4 ∙ 8 = 3

y - 2 = 3

Add 2 to both sides

y = 5

The solution is ( 8 , 5 )