Question

Tính

a) (2m-7)²

b) (3m-1)³

c) (5x+12)²

d) (3-z²)²

e) (4a+7b)³

f) (x+y²)²

g) (2x-z)³

h) (3y+\(\dfrac{1}{2}\))³

Answer 1

a)(2m-7)^2=(2m)^2-2.2m.7+7^2= 4m^2-28m+49

b)(3m-1)^3=(3m)^3-1^3-3.3m.1(3m-1)=9m^3-1- 27m^2-9m

c)(5x+12)^2=(5x)^2+2.5x.12+12^2=25x^2+120x+144

d)(3-z^2)^2=3^2- 2.3.z^2+(z^2)^2=9-6z^2+z^4

e)(4a+7b)^3=(4a)^3+(7b)^3+3.4a.7b(4a+7b)=64a^3+343b^3+336a^2b+588ab^2

f)(x+y^2)^2=x^2+2x.y^2+(y^2)^2=x^2+2xy^2+y^4

g)(2x-z)^3=(2x)^3-z^3-3.2x.z(2x-z)=8x^3-z^3-12x^2z+6xz^2

h)(3y+1/2)^3=(3y)^3+(1/2)^3+3.3y.1/2(3y+1/2)=27.y^3+1/8+27/2.y^2+9/4.y