intermediate algebra

[hopen2impov]

SUBTRACT

(30x +22xy -7y) - (10x -23xy -20y)
30x +22xy -7y -10x +23xy +20y
30x -10x +22xy +23xy -7y+20y
=20x^2 +45x^2y^2 +13y^2

 

[wjm11]

(30x +22xy -7y) - (10x -23xy -20y)
30x +22xy -7y -10x +23xy +20y
30x -10x +22xy +23xy -7y+20y
=20x^2 +45x^2y^2 +13y^2

You omitted all the exponents (apparently) in the initial steps, so I cannot positively determine if you combined like terms.

 

[hopen2impov]

30x +22xy -7) - (10x -23xy -20y)
30x +22xy -7y -10x +23xy +20y
20x +43xy +13y is this ok?

 

[mmm4444bot]

30x - 10x + 22xy + 23xy - 7y + 20y

20x^2 + 45x^2y^2 + 13y^2 We don't mutliply any x or y times any other x or y.

The only operations are addition and subtraction. No multiplying.

30x - 10x = 20x

If you take 10 x's away from 30 x's, there are 20 x's left.

 

[mmm4444bot]

20x + 43xy + 13y is this ok?

This is better, but the middle coefficient (in red) is wrong. Maybe that's a typographical error because you had it correctly on your first attempt.

 

[hopen2impov]

thank you for your advice and help, i won't muiltiply the exponents when i'm adding or subtracting.