her mistake is on line 2. it should be negative 3 not positive 3.
the rectangles area is lw and we know that 2x + 17 = 6x + 9 because they are both the length. so to find x we do an equation and isolate x like this
2x + 17 = 6x + 9
subtract 9 on both sides
2x + 8 = 6x
subtract 2x to both sides
8 = 4x
divide both sides by 4
2 = x
switch the sides to maintain proper form
x = 2
so now we know x = 2 so to find the answer we need to do length times width. for length im going to use 2x + 17 but you can use 6x + 9 if you want.
(2(2) + 17) (4(2) - 1)
(4 + 17) (8 - 1)
22 7
154 units squared
