<span> When area is equal 1120. We can write an equation (x+4)(-x+64)=1120 -x²-4x+64x+256=1120 -x²+60x+256-1120=0 -x²+60x-864=0 D=b² - 4ac= 3600-4*864=144, √D=12 x= (-b+/-√D)/2a x=(-60+/-12)/(-2) x=24, x=36 For x=24 (x+4)=24+4=28 (-x+64)=(-24+64)=40 For x=36 (x+4)=36+4=40 (x-64) =(-36+64)=28 So sides should be 28 and 40 in. We did not get any extraneous solutions. They could be if we get negative length side, for example. They can come because a quadratic equation can give positive and negative numbers because a^2 and (-a)^2 give the same positive number. We chose to solve this equation using formula for quadratic equations, because this equation has too big numbers to solve it using other methods.
