Question

a) (𝑥2+1)(𝑥−3)−(𝑥−3)(𝑥2+3𝑥+9)

b) (𝑥+2)2+𝑥(𝑥+5)

c) (5𝑥+4𝑦)(5𝑥−4𝑦)−24𝑥2+15𝑦2

Answer 1

tl mình nha

Answer 2

a) \(\left(x^2+1\right)\left(x-3\right)-\left(x-3\right)\left(x^2+3x+9\right)\)

\(=\left(x-3\right)\left[x^2+1-\left(x^2+3x+9\right)\right]\)

\(=\left(x-3\right)\left(x^2+1-x^2-3x-9\right)\)

\(=\left(x-3\right)\left(-3x-8\right)\)

Answer 3

b) \(\left(x+2\right)^2+x\left(x+5\right)\)

\(=x^2+4x+4+x^2+5x\)

\(=2x^2+9x+4\)

c) \(\left(5x+4y\right)\left(5x-4y\right)-24x^2+15y^2\)

\(=25x^2-16y^2-24x^2+15y^2\)

\(=x^2-y^2\)

\(=\left(x+y\right)\left(x-y\right)\)