求帮助！初二数学题，因式分解

Question

2x^2+20x+50
8m^2-24m+18
27c^2-18cd+3d^2
-63y^2-28x^2-84xy
p^2-(p+q)^2
2-18(a+1)^2
25(x+1)^2-16(x-1)^2

要答案和过程谢谢

Answer 1

解
2x²+20x+50
=2(x²+10x+25)
=2(x+5)²

8m²-24m+18
=2(4m²-12m+9)
=2(2m-3)²

27c²-18cd+3d²
=3(9c²-6cd+d²)
=3(3c-d)²

-63y²-28x²-84xy
=-7(9y²+12xy+4x²)
=-7(3y+2x)²

p²-(p+q)²
=[p-(p+q)][p+(p+q)]
=-q(2p+q)

2-18(a+1)²
=2[1-9(a+1)²
=2[1-3(a+1)][1+3(a+1)]
=2(-3a-2)(3a+4)
=-2(3a+2)(3a+4)

25(x+1)²-16(x-1)²
=[5(x+1)-4(x-1)][5(x+1)+4(x-1)]
=(x+9)(9x+1)