Dividing by 2, we have S/2=lw+lh+wh. After that, we subtract lh from both sides to get S/2-lh=lw+wh. Next, we divide both sides by w to get (S/2)/w=l+h. Next, we divide by S/2 to get 1/w=(l+h)/(S/2). Lastly, we multiply by w and divide by (l+h)/(S/2) to get w=(S/2)/(l+h)
Let garret’s age be x
x + 2 + (x + 3) + 2 = 39
2x + 7 = 39
2x = 32
x = 32/2
x = 16
Garrett’s age after two years = 16 + 2 = 18
46
When it says f(4) that means x=4
So you then just fill in all the x’s with 4’s and solve as normal