Hello please help ty

i think a but not sure

Step-by-step explanation:

i always second guess myself but a was first answer for me

The 3rd one (7+3)a^4

Step-by-step explanation:

This is because you have to distribute everything in the parentheses to (a) to the fourth power.

Hope this helps.

57 732

step-by-step explanation:

i dont really.know

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