Hey!
The formula for finding area of a triangle is: (base × height) ÷ 2
The base is 4
The height is 12
12 × 4 = 48
48 ÷ 2 = 24

Substitute the value of b = -2 to the expression

250 = 167.93 + x
[She needs $250, she has $167.93, and she needs x more. x represents the amount of money she still needs in order to get 250]
250 = 167.93 + x Subtract 167.93 on both sides
250 - 167.93 = 167.93 + x - 167.93
250 - 167.93 = x
82.07 = x
She needs $82.07 more
Or you could have done:
250 - 167.93 = 82.07
36*40+36*40-6*6=2844ft^2
we had to subtract the area of the closet so it wasn't counted twice :P