Help i m not smart at all see alot

-3

Step-by-step explanation:

You have to bring -16 to the other side by adding.

It would make it: -7a=21

Then you hve to diving the -7.

-7a/-7=21/-7

That would equal -3

A= -3

Step-by-step explanation:

-7a - 16 = 5

( -7a - 16) + 16 = 5 + 16

-7a - 16 + 16 = 21

-7a = 21

7a/7 = - 21/7

a = -3

Hope this helps you

Brainless please

im alright what do you need

step-by-step explanation:

c.

step-by-step explanation:

she should of added 9^2 and 12^2. that is because it is a^2+b^2=c^2. c^2 is the hypotenuse and should always be bigger than the other two numbers. which is why she should of added 9 squared and 12 squared together instead of 15 squared.