Find the value of the expression: 2xy+2x^2 for x=−2.5 and y=−7.5

Suppose that the price p (in dollars) and the weekly sales x (in thousands of units) of a certain commodity satisfy the demand equation 4p cubedplusx squaredequals38 comma 400. determine the rate at which sales are changing at a time when xequals80, pequals20, and the price is falling at the rate of $.20 per week.

Find the slope and the y-intercept if there's one and the equation of the line given these two points( 3, 2) and( 3, -4)

What is the answer to this question? i'm a bit stumped. also how do i do it? 5(x - 4) = 2(x + 5)