4X2+X3+3X+7Y+2X3 can only be simplified to 3X3+4X2+3X+7Y, because X3 and 2X3 are the only like terms.
7y+5=-9... 7y must equal -14 therefore y must be -2
8y - 38
That depends what you want it to equal at the end.
a + 7y
16+7y-8 = 7y+16-8 = 7y+8
-7y + 4y = -3y
39 - 7y = 18,-7y = 18 - 39-7y = -21-7y/-7 = -21/-7y = 3
3y=7y+24.4 First, try to get all the y-terms on the same side of the equation. Easily done here by subtracting 7y from both sides 3y-7y=7y-7y+24.4 -4y=24.4 Now divide by -4 -4y/-4=24.4/-4 y=-6.1
-6y+3 = -7y+8 -6y+7y = 8-3 y = 5
7y + 4 - 4 - 9 = 7y - 9
x = 7y x/7 = y