Question

x-3y=-12
2x+3y=11 solve by using elimination

Answer 1

x-3y=-12
2x+3y=11

3x 0 = -1
3x=-1
x=-1/3

Answer 2

x - 3y = -12
2x + 3y = 11
--------------add
3x = - 1
x = -1/3

now sub -1/3 in for xin any of the original equations
x - 3y = -12
-1/3 - 3y = -12 (multiply the equation by 3 to get rid of the fractions)
-1 - 9y = - 36 (add 1 to each side)
-9y = -36 + 1
-9y = -35
y = -35/-9
y = 35/9

check...
2x + 3y = 11
2(-1/3) + 3(35/9) = 11
-2/3 + 105/9 = 11 (common denominator is 9)
-6/9 + 105/9 = 11
99/9 = 11
11 = 11 (correct)

x = -1/3
y = 35/9