(2)p^2+3pq+6-8p^2+pq=-7p^2+4pq+6

(3)(7y-3z)-(8y-5z)=-y+2z

(4)-(a^5-6b)-(-7+3b)=-a^5+6b+7-3b=-a^5+3b+7

(5)2(2a^2+9b)+3(-5a^2-4b)=4a^2+9b- 15a^2-4b=- 1 1a^2+5b

(6)-3(2x^2-xy)+4(x^2+xy-6)=-6x^2+3xy+4x^2+4xy-24=-2x^2+7xy-24

4.( 1) 9x+6x2-3 (x-2/3x2), where x=-2.

9x+6x^2-3x+ 1 1/3x^2=6x+29/3x^2=6*(-2)+29/3*(-2)=- 12-58/3=-94/3

(2)1/4 (-4x2+2x-8)-(1/2x-1), where x= 1/2.

-x^2+ 1/2x-2- 1/2x+ 1=- 1/2^2+ 1/4-2- 1/4+ 1= 1/4- 1=-3/4

(3) (5a 2-3b 2)+(a 2+b 2)-(5a 2+3b 2), where a =- 1 and b = 1.

5a^2-3b^2+a^2+b^2-5a^2-3b^2=5-3+ 1+ 1-5-3=-6+2=-4

(4) 2 (A2B+AB 2)-2 (A2B-1)-2AB 2-2, where a =-2 and b = 2.

2a^2*2b+2ab^2-2a^2*2b*2-2ab^2-2=8*4-4*4-8*4*2+4*4-2=- 18

Note: give more, or I won't answer your question next time! It's hard for me to do this! )