Can someone pls help me with 15 and 18 ?

[tex] \frac x 5 -g = a[/tex]
[tex] \frac x 5= a + g[/tex]
[tex]x = 5(a+g)[/tex]
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[tex]g(h + \frac 2 3 ) = 1[/tex]
[tex]h + \frac 2 3 = \frac 1 g[/tex]
[tex]h = \frac 1 g -\frac 2 3[/tex]
x/5 - g = a Solve for x
x/5 = a + g Add g to both sides of the equation
x = 5(a + g) Multiply both sides of the equation by 5
g(h + 2/3) = 1 Solve for h
gh + 2/3g = 1 Distribute
gh = 1 - 2/3g Subtract 2/3g
h = 1/g - 2/3 Divide by g to isolate h
Hope that helps!