7(c + 5) − f 4 ; c = −1, f = 3
Can someone explain how to solve this?

16

Step-by-step explanation:

you replace the letter with the number given to replace them. So, in the equation you replace the letter C with -1, as it tell you on the side. You do the same with F, but with 3. your equation should look like: 7(-1 + 5) - 3 × 4. you then solve from there and should get 16. I hope this is right, if not my bad

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

step-by-step explanation: