(Distribute) 6y-15=4y-7
(sub. 4y) 2y-15=-7
(add 15) 2y=8
(divide by 2) y=4
B Q6)9+4y=2(3-y)
(Distribute) 9+4y=6-2y
(add 2y) 9+6y=6
(subtract 9) 6y=-3
(divide by 3) y=-1/2
B Q7)3x-3=3/4(2x+12)
(move terms to left side) 3x-3-3/4(2x+12)=0
(transform into fraction) (3x-3)-(3(2x+12)/4)=0
(common denominator, Multi. by 4) (4(3x-3))/4-(3(2x+12))/4 = 0
(add fractions) (4(3x-3)-3(2x+12))/4=0
(distribute) (12x-12-6x-36)/4
(combine like terms) (6x-48)/4
(factor) (3(x-8))/2=0
(if fraction = 0, numerator =0) x-8=0
(add 8) x=8