Need help on number 6 and 7 I am not good at algebra in the slightest

For #6:

I believe the answer is 1) −15x^3y^3−3x^3y^2

For # 7:

I got 3) 3

First, in order to isolate the variable "x"  you need to distribute:

13x - 2(x + 4) = 8x + 1

13x -2x - 8 = 8x + 1

Then you need to combine like terms

13x - 2x - 8 = 8x + 1

11x - 8 = 8x + 1

Add 8 to both sides

11x = 8x + 9

Subtract 8x on both sides

3x = 9

Now you can divide both sides by 3...

Thus x = 3

I'm actually taking algebra right now and I gotta admit algebra is tricky for sure. However, I think it'll get easier with practice  :D