b) Ta có: \(R=x^3+3x^2+3x+1\)
\(=\left(x+1\right)^3\)
\(=100^3=1000000\)
e) Ta có: \(M=\left(x+y\right)^3+2x^2+4xy+2y^2\)
\(=\left(x+y\right)^3+2\left(x^2+2xy+y^2\right)\)
\(=\left(x+y\right)^2\cdot\left(x+y+2\right)\)
\(=7^2\cdot\left(7+2\right)\)
\(=49\cdot9=441\)
a) Ta có: \(A=x^3+15x^2+75x+125\)
\(=\left(x+5\right)^3\)
\(=\left(-10+5\right)^3=\left(-5\right)^3=-125\)
q) Ta có: \(Q=x^3+\dfrac{3}{10}x^2+\dfrac{3}{100}x\)
\(=\left(\dfrac{9}{10}\right)^3+\dfrac{3}{10}\cdot\dfrac{81}{100}+\dfrac{3}{100}\cdot\dfrac{9}{10}\)
\(=\dfrac{729}{1000}+\dfrac{243}{1000}+\dfrac{27}{1000}\)
\(=\dfrac{999}{1000}\)
giúp mình bài 4 câu B,C D với ạ
