Question 62320
I'LL DO THE FIRST TWO FOR YOU.
(1/3)(3Y+12)=-5Y-4(Y-6)
Y+4=-5Y-4Y+24
Y+5Y+4Y=24-4
10Y=20
Y=20/10
Y=2
PROOF
(1/3)(3*2+12)=-5*2-4(2-6)
(1/3)(6+12)=-10-4(-4)
1/3*18=-10+16
6=6
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(4+3X)/5+(7-X)/3=(7/15)
[3(4+3X)+5(7-X)]/15=7/15
(12+9X+35-5X)/15=7/15 MULTIPLYING EACH SIDE BY 15 ELIMINATES THE DENOMINATORS.
9X-5X=7-12-35
4X=7-47 
4X=-40 DIVIDE BOTH SIDES BY 4
4X=-40/4
X=-10
PROOF
(4-30)/5+(7+10)/3=7/15
-26/5+17/3=7/15
(3*-26+17*5)/15=7/15
(-78+85)/15=7/15
7/15=7/15