Answer:
D. It has a single solution: x=-3, y= 26.
Step-by-step explanation:
3x + y=17
Subtract 3x so it is in y=mx+b form. So now it is y= -3x +17
Now plug in
x + 2 (-3x+17) = 49
x + -6x + 34 = 49 (distribute)
-5x = 15 (combine the x terms and subtract 34 on both sides)
x = -3 (divide -5 on both sides to get x alone)
now plug in x into any other equation to get y
x + 2y = 49
-3 + 2y = 49
2y = 52 (add 3 on both sides)
y = 17 (divide 2 on both sides to get y alone)
(-3, 26)