What is the algebraic expression for "the difference between seven times a number and three times that number"?

7 - 3x
7x - 3
7x - 3x

He weights of 2-pound bags of best dog food are approximately normally distributed with a given mean  and standard deviation  according to the empirical rule, what percentage of the bags will have weights within 3 standard deviations of the mean? 47.5%68%95%99.7%

50 plz, given the system of equations, match the following items. x + 3 y = 5 x - 3 y = -1 a) x-determinant b) y-determinant c) system determinant match the following to the pictures below.

Select the conic section that represents the equation. 3x2 + 3y2 -2x + 4 = 0