Twice the sum of a number x and 18 as an expression

Will used 20 colored tiles to make a design in art class. 5/20 of his tiles were red. what is an equivalent fraction for the red tiles?

How do i do this? i don’t understand

Use the quadratic formula to solve the equation. if necessary, round to the nearest hundredth. x^2 - 8 = -6x a. –7.12, 1.12 b. 7.12, –1.12 c. 7.12, 1.12 d. –7.12, –1.12