a, \(A=\left(100+50\right)^2=22500\)
b, \(B=\left(127+73\right)^2=40000\)
c, \(C=-6x+25\)Thay x = 100 ta có :
\(C=-6.100+25=-600+25=-575\)
\(A=100^2+200.50+50^2\)
\(=100^2+2.100.5+50^2\)
\(=\left(100+50\right)^2=150^2\)
\(B=127^2+146.127+73^2\)
\(=127^2+2.73.127+73^2\)
\(=\left(127+73\right)^2=200^2\)
\(C=\left(x-3\right)^2-\left(x+4\right)\left(x-4\right)\)
\(=x^2-6x+9-x^2+16=25-6x\)
\(=25-600=-575\)
\(D=\left(2x-3y\right)\left(4x^2+6xy+9^2\right)=8x^3-27y^3\)
bạn thế vô là xong