Math F.1

1) (3m+5)(7-2m)
=21m+35-6m^2-10m
=6m^2+11m+35
2) (3p-4q)^2
=(3p)^2-2(3p)(4q)+(4q)^2
=9p^2-24pq+16q^2
3) (8a^8-12a-20)-(6a^4-3a^3-5)
=8a^8-6a^4-3a^3-12a-20+5
=8a^8-6a^4-3a^3-12a-15
4) (4)(2a^2-3a-5)-(3a^2)(2a^2-3a-5)
=(a^2-3a-5)(4-3a^2)
5) (a^2-2a-1)(2-a+3a^2)
=2a^2-4a-2-a^3+2a^2+a+3a^4-6a^3-3a^2
=3a^4-7a^3+a^2-3a-2

1) (3m+5)(7-2m)
= 3m(7-2m)+5(7-2m)
= 21m-6m^2+32-10m
= -6m^2+21m-10m+32
= -6m^2+11m+32 (答案)

2) (3p-4q)^2
= (3p-4q)(3p-4q)
= 3p(3p-4q)-4q(3p-4q)
= 9p^2-12pq-12pq+16q^2
= 9p^2-24pq+16q^2 (答案)

3) (8a^8-12a-20)-(6a^4-3a^3-5)
= 8a^8-12a-20-6a^4+3a^3+5
= 8a^8-6a^4+3a^3-12a-20+5
= 8a^8-6a^4+3a^3-12a-15 (答案)

4) (4)(2a^2-3a-5)-(3a^2)(2a^2-3a-5)
= 8a^2-12a-20-6a^4+6a^3-15a^2
=8a^2-15a^2-12a-20-6a^4-6a^3
=-7a^2-12a-20-6a^4-6a^3(答案)

5(a^2-2a-1)(2-a+3a^2)
=a^2(2-a+3a^2)-2a(2-a+3a^2)-1(2-a+3a^2)
=2a^2-a^3+3a^4-4a+2a^2-6a^3-2+a-3a^2
=2a^2+2a^2-3a^2-a^3-6a^3+3a^4-4a+a-2
=a^2 - 7a^3+3a^4-4a+a-2

1) (3m+5)(7-2m)
=3m(7-2m)+5(7-2m)
=21m-6m^2+35-10m
= -6m^2+11m+35

2) (3p-4q)^2
=(3p)^2-2(3p)(4q)+(4q)^2
=9p^2-24pq+16q^2

3) (8a^8-12a-20)-(6a^4-3a^3-5)
=8a^8-12a-20-6a^4+3a^3+5
=8a^8-6a^4+3a^3-12a-20+5
=8a^8-6a^4+3a^3-12a-15

4) (4)(2a^2-3a-5)-(3a^2)(2a^2-3a-5)
=8a^2-12a-20-6a^4+9a^3+15a^2
= -6a^4+9a^3+15a^2+8a^2-12a-20
= -6a^4+9a^3+23a^2-12a-20

5) (a^2-2a-1)(2-a+3a^2)
=(a^2-2a-1)(3a^2-a+2)
=a^2(3a^2-a+2)-2a(3a^2-a+2)-(3a^2-a+2)
=3a^4-a^3+2a^2-6a^3+2a^2-4a-3a^2+a-2
=3a^4-a^3-6a^3+2a^2+2a^2-3a^2-4a+a-2
=3a^4-7a^3+a^2-3a-2