Question

Bài 1: Viết các biểu thức sau dưới dang tổng 

a.(1/2+x)^2 ; (2x+1)^2

b.(2x+3y)^2;(0,01+xy)^2

c (x+1)*(x-1)

d.(x-2y(x-2y);(56*64)

Answer 1

a, \(\left(\frac{1}{2}+x\right)^2=\left(\frac{1}{2}\right)^2+2.\frac{1}{2}.x+x^2=\frac{1}{4}+x+x^2\)

\(\left(2x+1\right)^2=\left(2x\right)^2+2.2x.1+1^2=4x^2+4x+1\)

b, \(\left(2x+3y\right)^2=\left(2x\right)^2+2.2x.3y+\left(3y\right)^2=4x^2+12xy+9y^2\)

\(\left(0,01+xy\right)^2=\frac{1}{10000}+\frac{1}{50}xy+x^2y^2\)

c, \(\left(x+1\right)\left(x-1\right)=x^2-1\)

d, \(\left(x-2y\right)\left(x-2y\right)=\left(x-2y\right)^2=x^2-4xy+4y^2\)

\(56.64=\left(60-4\right)\left(60+4\right)=60^2-4^2\)