Match the equations to the lines below : y = 1/2x - 1
y= -1/2x + 1
y= 1/2x + 1
y= -2x - 1
y= 2x - 1
y= -1/2x - 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%)