Which shows the correct substitution of the values a, b, and c from the equation-

2

+X4 into the quadratic formula?

Quadratic formula: x = -by- Aac

29

x = -(-1) *V(1)2 - 4(1) – 4)

2(1)

-1 V12-4-1)(-4)

2(-1)

x= -1*V(1)2 - 4 - 1)(-2)

21-1)

x==(-1):71-232 - 4(13–3)

2(1)

Astudent must have an average on five test that is greater than it equal to 80% but less than 90% to receive a final grade of b. devon's greades on the first four test were 78% 62% 91% and 80% what range if grades on the fifth test would give him a b in the course? ( assuming the highest grade is 100%)