Let's solve the following expressions:
a.) 7 - (5t - 13) = -25
[tex]\text{ 7 - (5t - 13) = -25}[/tex][tex]\text{ 7 - 5t + 13 = -25}[/tex][tex]\text{ 20 - 5t = -25}[/tex][tex]\text{-5t = -25 - 20}[/tex][tex]\text{-5t = -4}5[/tex][tex]\frac{\text{-5t}}{-5}\text{ = }\frac{\text{-4}5}{-5}[/tex][tex]\text{ t = 9}[/tex]Therefore, t = 9
b.) -15b + 21 + 5b = -19
[tex]-15b+21+5b=-19[/tex][tex]-10b+21=-19[/tex][tex]-10b=-19\text{ - 21}[/tex][tex]-10b=-40[/tex][tex]\frac{-10b}{-10}=\frac{-40}{-10}[/tex][tex]\text{ b = 4}[/tex]Therefore, b = 4
