Three times a number subtracted by 3 is 20

Find an equation (in term of x) of line through the points (-1,3) and (1,4)

Simplify (a/b - b/a) times (a - a^2/a+b) a - a^2/a=b is a mixed number

The function a represents the cost of manufacturing product a, in hundreds of dollars, and the function b represents the cost of manufacturing product b, in hundreds of dollars. a(t) = 5t + 2 b(t) = 7t - 2t +4 find the expression that describes the total cost of manufacturing both products, a(t) + b(t). a. 7t^2 - 7t + 2 b. 7t^2 + 3 +6 c. 7t^2 + 7t - 6 d. 7t^2 - 3t + 6