# Math

posted by .

Hi, would someone mind just checking the answer I got for this formula and tell me if I'm on the right track or not.
Question...

x+y=21
3x=4y

x=84 y= -63

I didn't get that. Check your math. I found 7y=63 but not y = 63.
3*84 = 4*63 yes, it is.Is X + Y = 21. No, it isn't. I always check my answers before I call it quits on a problem.

yyes you are right

wat is the answer to this ?

w+4(w+3)

solve by elimination

4x-3y=21
-4x-2y=-6

• Math -

y=-3 , x=3

• Math -

x+y=21(*)
3x-4y=0 (**)
(*)=>x=21-y
Replace to (**):=> 3(21-y)-4y=0
=>63-3y-4y=0
<=>7y=63=>y=63/7=9
y=9 replace (*)=>x=21-9=12
=>x=12
y=9

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