What substitution should be used to rewrite 4x^4-21x^2+20=0

(a.s."similarity in right triangles"solve for xa.) 10b.) 20c.) 14.5d.) [tex] 6\sqrt{3} [/tex]

Which point-slope form equation represents a line that passes through (3,-2) with a slope of -4/5

Arestaurant offers delivery for their pizzas. the total cost the customer pays is the price of the pizzas, plus a delivery fee. one customer pays $23 to have 2 pizzas delivered. another customer pays $59 for 6 pizzas. how many pizzas are delivered to a customer who pays $86?