18. let e = {u1, u2, u3} and f = {b1, b2}, where u1 = ⎧⎩ 1 0 −1 ⎫⎭ , u2 = ⎧⎩ 1 2 1 ⎫⎭ , u3 = ⎧⎩ −1 1 1 ⎫⎭ and b1 = (1,−1)t , b2 = (2,−1)t for each of the following linear transformations l from r3 into r2, find the matrix representing l with respect to the ordered bases e and f: (a) l (x) = (x3, x1)t (b) l (x) = (x1 + x2, x1 − x3)t (c) l (x) = (2x2,−x1)t

Aretha wanted to gather data about the cost of local bowling leagues in her area. she plotted the data and determined that the average bowling league costs consist of a one-time registration fee and a monthly fee modeled by the equation y = 15x + 20. identify and interpret the y-intercept in this model. the y-intercept is 20. this is the cost per month. the y-intercept is 20. this is the cost of registration. the y-intercept is 15. this is the cost of registration. the y-intercept is 15. this is the cost per month.

Solve each quadratic equation by factoring and using the zero product property. [tex]x^2+6x+8=0[/tex]

Two friends are reading books. jimmy reads a book with 21,356 words. his friend bob reads a book with one-and-a-half times as many words. which expression represents the number of words bob reads?