First equation:
Start with
[tex] 30-5a = 50 [/tex]
Subtract 30 from both sides:
[tex] -5a = 20[/tex]
Divide both sides by -5:
[tex] a = -4 [/tex]
Second equation:
Start with
[tex] \dfrac{1}{4}(b-10) = -6 [/tex]
Multiply both sides by 4:
[tex] b-10 = -24 [/tex]
Add 10 to both sides:
[tex] b = -14 [/tex]
