Factor the polynomial by grouping: 12x^3-28x^2-15x+35

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ab=4 and bc=3, find ah, ch and bh.

There is a line with slope 1/a going through the point (a, a²). find the equation of the line perpendicular to this line at this point. (don’t let this problem intimidate you! solve the problem as you would if i’d given you specific values. just use variables instead.)

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