Question

-9x+y=71, 6x+12y=54 Solve by Substitution method.

Answer 1

Substitution method

Given first equation is -9x+y = 71

Add 9x to each side.

y = 9x+71 ---> (1)

Second equation is 6x+12y = 54 ---> (2)

From (1) substitute the y value in (2).

6x+12(9x+71) = 54

6x+108x+852 = 54

114x = 54-852

x = -798/114

x = -7

Substitute the x value in (1)

y = -63+71

y = 8

Solution x = -7, y = 8.