Blackberries are on sale for $3.94 per pound. What is the standard equation?

What is the point-slope form of the equation for the line with a slope of -2 that passes through (1,4)?

Which equation represents the line that passes through the points and (4, 10) and (2, 7)? y = 3/2x - 11y = 3/2x +4y = - 3/2x + 19y = - 3/2x + 16

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?