Am i doing this right?
(5x+10)^2 = 40
(5x+10)(5x+10)= 40
25x^2 + 100x + 100 = 40
25x^2 + 100x + 60 = 0
once i get that last equation i do this
(-100 (+/-) sq(10000-6000))/50
then i simply this far
(-80 sq(10))50 and (-120 sq(10))/50
but the multiple choice answers dont look like what i got :/