The variables x and y vary directly. Given the model y = -2x , find the value of x when y = -16.
a. 8
32
b. 16
d. 64
C.

Mary used 1/7 of a spool of ribbon to complete 4 projects. she used the same amount of ribbon on each project. how much ribbon did she use on each project?

What does x = in this equation x+3+2x=x+5

For what values of the variable x is the expression square root of 7x+14+ square root of 7-x a real number?