Question

giải gấp giúp tớ với ạa

Answer 1

B2:

\(a.\left(2+xy\right)^2\\ =2^2+2\cdot xy\cdot2+\left(xy\right)^2\\ =4+4xy+x^2y^2\\ b.\left(5-3x\right)^2\\ =5^2-2\cdot5\cdot3x+\left(3x\right)^2\\ =25-30x+9x^2\\ c.\left(5x-1\right)^3\\ =\left(5x\right)^3-3\cdot\left(5x\right)^2\cdot1+3\cdot5x\cdot1^2-1^3\\ =125x^3-75x^2+15x-1\\ d.\left(2x-y\right)\left(4x^2+2xy+y^2\right)\\ =\left(2x\right)^3-y^3\\ =8x^3-y^3\\ d.\left(x+3\right)\left(x^2-3x+9\right)\\ =x^3+3^3\\ =x^3+27\\ e.\left(5-x^2\right)\left(x^2+5\right)\\ =\left(5-x^2\right)\left(5+x^2\right)\\ =5^2-\left(x^2\right)^2\\ =25-x^4\)