Question

Select the TWO systems of equations that have exactly one solution

A. y= 3x + 1
y= -3x + 7

B. y= 3x + 1
y = x + 1

C. y= 3x + 1
y = 3x + 7

D. x + y = 10
2x + 2y = 20

E. x + y = 10
x + y = 12

Answer 1

A. if you replace x by 1 the answer for both equations is 4

Answer 2

D

Explanation:

for D

let (x,y) = (5,5)

5+5=10

5+5=102×5+2×5=20

let (x,y) = (6,4)

6+4=10

6+4=102×6+2×4=20