упростите

(3a+5)(3a-6) +30 = 9a-18a+15a-30+30= 9a-3a =
можно вынести общий множитель:
= 3a(3a-1)

8х -(3х+1)(5х+1) = 8х -(15х+3х+5х+1)=
= 8х - 15х-8х-1 = -15х-1

(х-3)(х+5)- (х+х) = х+5х -3х-15-х-х=
= х-15

(у+2)(у+3)-у(у-1) = у+3у +2у +6 - у+у =
= 6у+6 = 6(у+1)

3b+(8-3b)(b+5) = 3b +8b +40 -3b-15b=
= -7b+40 

8p -(3p+8)(2p-5)= 8p - (6p-15p +16p-40)=
= 8p -( 6p +p-40) = 8p -6p-p+40=
= -6p +7p+40

a(a-3) + (a+1)(a+4) = a-3a + a+4a +a+4 =
= 2a+2a+4 = 2(a+a+2)

(c+2)c -(c+3)(c-3)= c+2c -(c-3) =
=c+2c-c+9 =2c+9