1. solve the system using substitution
x+y=8
y=3
a.(4,12)
b.(2,6)
c.(1/2,2/3)
,-12)

X + y = 8
y = 3

Well, because we know what y equals, we simply plug in 3 for y in the given equation.

x + y = 8

x + (3) = 8

Subtract 3 from both sides.

x = 8 - 3

So, x = 5

(5, 3)

Check work by plugging in x and y in the given equation.

x + y = 8

(5) + (3) = 8

8 = 8

So, our answer is (5, 3)

I am quite sure that you have given us the wrong equations, as none of these answers are correct.

~Hope I helped!~