Question

(9x² - 16x - 4) -(15x -12x²+5)​

Answer 1

Answer:

$\blue{\left(9x^2-16x-4\right)-\left(15x-12x^2+5\right)=21x^2-31x-9}$

Step-by-step explanation:

$\left(9x^2-16x-4\right)-\left(15x-12x^2+5\right)$

$\gray{\mathrm{Remove\:parentheses}:\quad \left(a\right)=a}$

$=9x^2-16x-4-\left(15x-12x^2+5\right)$

$\black{-\left(15x-12x^2+5\right):}$

$\gray{\mathrm{Distribute\:parentheses}}$

$=-\left(15x\right)-\left(-12x^2\right)-\left(5\right)$

$\gray{\mathrm{Apply\:minus-plus\:rules}}$

$\gray{-\left(-a\right)=a,\:\:\:-\left(a\right)=-a}$

$=-15x+12x^2-5$

$=9x^2-16x-4-15x+12x^2-5$

$\black{\mathrm{Simplify}\:9x^2-16x-4-15x+12x^2-5:}$

$9x^2-16x-4-15x+12x^2-5$

$\gray{\mathrm{Group\:like\:terms}}$

$=9x^2+12x^2-16x-15x-4-5$

$\gray{\mathrm{Add\:similar\:elements:}\:-16x-15x=-31x}$

$=9x^2+12x^2-31x-4-5$

$\gray{\mathrm{Add\:similar\:elements:}\:9x^2+12x^2=21x^2}$

$=21x^2-31x-4-5$

$\gray{\mathrm{Subtract\:the\:numbers:}\:-4-5=-9}$

$=21x^2-31x-9$

Answer 2

Answer:

9x² -16x - 4

-12ײ+15x+ 5

(+) (-) (-)

___________

21x² -31x -9

___________

Step-by-step explanation: