15. 2x-5=-20
2x=-15; Add positive 5 on both sides to isolate x.
x=[tex] \frac{-15}{2} [/tex]; Divide 2 on both sides to find the value of x.
17. [tex] \frac{9x}{4} [/tex]=-9
9x=-36; Multiply positive 4 on both sides of the equation.
x==-4; Divide 9 on both sides of the equation to find the value of x.
