Ac method for x^2+20x-8=0

Me! i will mark brainliest! i don't get polynomials and all that other stuff. so this question is really hard. multiply and simplify.(x - 4) (x^2 – 5x – 6)show your

In trapezoid abcd, ac is a diagonal and ∠abc≅∠acd. find ac if the lengths of the bases bc and ad are 12m and 27m respectively.

Travis and paula went to lunch. travis ordered a sandwich for $7.50 and paula ordered a burger for $5.25.after lunch, they left a 15% tip for the waiter. how many money did they spend altogether?