Question

8x+y=-16 -3x+y=-5 _________

Answer 1

Answer:

x = -1

y = -8

Step-by-step explanation:

to evaluate this system of equation using the substitution methods, we would say that let

8x+y=-16.................................................. equation 1

-3x+y=-5................................................... equation 2

from equation 2

-3x+y=-5................................................... equation 2

y = -5 + 3x ................................................. equation 3

substitute for y into equation 1

8x+y=-16.................................................. equation 1

8x + ( -5 + 3x) = -16

8x - 5 + 3x = -16

collect the like terms

8x + 3x = -16 + 5

11x = -11

divide both sides by the coefficient of x

11x/11 = -11/11

x = -1

put the value of x = -1 into equation 3

y = -5 + 3x ................................................. equation 3

y = -5 + 3(-1)

y = -5 - 3

y = -8

Answer 2

Multiply the second question by -1 to cancel out the y’s. then add them. 11x=-11
x=-1
substitute that back into one of the equations
-3(-1)+y=-5
3+y=-5
y=-8