solve each equation. function

Question

The square root and it had no number on the left side of the square root sign but under the sign it says -4-13k=10

 

I know the answer is -8 because we went over it in class but i still dont understand how she got that answer ive tried. its practive for my final tomorrow so if you can get back to me that would be wonderful thanks!

Answer 1

√(-4 - 13k) = 10

 

Square both sides to get rid of the square root:

 

     -4 - 13k = 100

 

Add 4 to both sides

 

     -13k = 104

 

Divide both sides by -13:

 

     k = -8