I need help with both of these

Step-by-step explanation:

1 . (4x² - 9x + 16) + (7 + 9x² - 10x)

4x² - 9x + 16 + 7 + 9x² - 10x

13x² - 19x + 23

2 . (-2x + 6) - (14x - 11)

-2x + 6 - 14x + 11

-16x +17

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15