Help please?

10x − 5y + 14 = 0 whats the answer pls

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%)

Its due 1. what is the product of 1/2-1/4? write your answer in standard form. a) show your work. b) is the product of 1/2x-1/4 and 5x^2-2x+6 equal to product of 1/4x-1/2 and 5x^2-2x+6? explain your answer.