Question

Khai triển các hằng đẳng thức sau:
a,(2x-3y)^2
b,(5p-q)^2
c,(-a-b)^2
d,(1+3s)^2
e,(a^2b+2b)^2
f,(3u-v)^3

Answer 1

a) \(\left(2x-3y\right)^2=4x^2-12xy+9y^2\)

b) \(\left(5p-q\right)^2=25p^2-10pq+q^2\)

c) \(\left(-a-b\right)^2=-a^2-2ab-b^2\)

d) \(\left(1+3s\right)^2=1+6s+9s^2\)

e) \(\left(a^2b+2b\right)^2=a^4b^2+4a^2b^2+4b^2\)

f) \(\left(3u-v\right)^3=27u^3-27u^2v+9uv^2-v^3\)

Answer 2

a,\(\left(2x-3y\right)=\left(2x\right)^2-2.2x.3y+\left(3y\right)^2\)

=\(4x^2-12xy+6y^2\)

b,\(\left(5p-q\right)^2=\left(5p\right)^2-2.5p.q+q^2\)

=\(25p^2-10pq+q^2\)

c,(-a-b)\(^2=\left(-a\right)^2-2.\left(-a\right).b+b^2\)

=\(a^2+2ab+b^2\)

d,\(\left(1+3s\right)^2=1+6s+9s^2\)

e,(a\(^2b+2b)^2=(a^2b)^2+2.a^2b.2b^2+\left(2b\right)^2\)

=\(a^4b^2+4a^2b^2+4b^2\)

f,\(\left(3u-v\right)^3=27u^3-27u^2v+9uv^2-v^3\)