Simple,
7.) Add [tex] -4x^{2}
and
3x^2
[/tex] to get.. [tex] -x^{2} +5x[/tex]
7.)[tex]- x^{2}+5x [/tex] (Answer)
8.) -7(y+4)-6y
Distribute the -7...
-7*y= -7y
and
-7*4=-28
Leaving you... -7y-28-6y
Add the -7y+-6y
8.) -13y-28 (Answer)
9.) 4xy+3x+6xy-9x+7x
Now it looks hard, but it's not, just go slowly...add apples and oranges...
4xy+6xy=10xy
and
3x-9x+7x=x
10xy+x
9.) 10xy+x (Answer)
If you have any doubts, just comment. :D
