Expand each of the following expressions.(step by step) (a) (x – 3)(x + 1)
(b) (x + 2)(x + 4)
(c) (1 – 7x)(11x – 4)
(d) (4 – 3x)(2 – 3x)
(e) (2x – 5)(7x – 11)
(f) (6 – d)(2d – 5)

The base of a triangle exceeds the height by 7 centimeters. if the area is 400 square centimeters, find the length of the base and the height of the triangle.

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ah=4 and hc=1, find bh.

1. writing an equation for an exponential function by 2. a piece of paper that is 0.6 millimeter thick is folded. write an equation for the thickness t of the paper in millimeters as a function of the number n of folds. the equation is t(n)= 3. enter an equation for the function that includes the points. (-2, 2/5) and (-1,2)