15 x 3= 45 so therefore 45 is the length hope that help!
Answer:
x=9, y=3
Step-by-step explanation:
-4x+6y=-18
y=-2x+21
-4x+6(-2x+21)=-18
-4x-12x+126=-18
144=16x
x=9
y=-2x+21
y=-18+21
y=3
See tha attached pdf file and let me know how useful this answer is.
