B1: tính nhẩm
\(101^2\)
\(72^2+56.72+28^2\)
\(45^2\)
\(34.46\)
B2 : Rút gọn
\(A=\left(x+5y\right)^2-5\left(x-2y\right)^2\)
\(B=\left(3x-4\right)^2-2\left(x+11\right)\left(x-11\right)\)
\(C=\left(3x-2y\right)^3-\left(4x-5y\right)\left(16x^2+20xy+25y^2\right)+\left(y+2x\right)^3\)
\(D=\left(x+5\right)\left(x^2-5x+25\right)-\left(x+3\right)^3+\left(x-2\right)\left(x^2+2x+4\right)-\left(x-1\right)^3\)
\(E=-5x\left(x-5\right)+\left(x-3\right)\left(x^2-7\right)\)
Tính
\(4x\left(x-5\right)-\left(x-1\right)\left(4x-3\right)=5\)
Giups mk vs nha !! thanks
