How do you multiply $(2x+3)(x^2+x-5)$ ?

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Answer 1 · 2015-06-25T08:20:42

$= color(blue)(2x^3 + 5x^2 -7x -15$

$color(blue)((2x+3))(x^2 + x - 5)$

Here, we first multiply $color(blue)(2x)$ contained in the first bracket with all three terms of second bracket:

$= color(blue)(2x).(x^2) + color(blue)(2x) .(x) + color(blue)(2x) . (-5)$

$= 2x^3 + 2x^2 -10x$ ........................ $(1)$

Now, we multiply $color(blue)(3)$ contained in the first bracket with all three terms of second bracket:

$= color(blue)(3).(x^2) + color(blue)(3) . x + color(blue)(3) . (-5)$

$= 3x^2 + 3x -15$ ......................... $(2)$

combining $(1)$ and $(2)$

$= color(blue)(2x^3 + 5x^2 -7x -15$

How do you multiply (2x+3)(x^2+x-5)(2x+3)(x^2+x-5)?