7th grade math check
posted by saranghae12 on .
Ok I was wondering if you could check these 3 problems please. I am suppose to set these equations equal but I am not sure if did them right. I think I accidently solved these systems as substitutions. The answers are suppose to be in coordinate pairs.
1) x  y = 11
3x + y = 21
I got (5,16)
2) 5x  4y = 17
10x + 4y = 42
I got (5,3)
3) x + 3y = 1
3x + 3y = 15
I got (4,1)
Please check if i did it correctly please. thank you

Check your solutions with both equations. If your solutions don't fit both, then your answers need to be reworked. For example, using the solution you have for 1):
x = 5
y = 16
5  (16) = 11 >false
3(5)  16 = 21 >false
Solution for this system should be (5,6).
5  (6) = 11 >true
3(5)  6 = 21 >true
Try the others again.