Use Gauss–Jordan reduction to solve each of the following systems. (a) x1 + x2 =−1 4x1 −3x2 = 3 (b) x1 +3x2 + x3 + x4 = 3 2x1 −2x2 + x3 +2x4 = 8 3x1 + x2 +2x3 − x4 =−1 (c) x1 +x2 +x3 =0 x1 −x2 −x3 =0 (d) x1 + x2 +x3 + x4 =0 2x1 + x2 −x3 +3x4 =0 x1 −2x2 +x3 + x4 =0

Triangle jkl was dilated using the rule dm, 1/3 the image, triangle j’ k’ l’ is the result of the dilation. a.5 units b.7.5 units c.10 units d.12.5 units

Mary beth used the mapping rule to find the coordinates of a point that had been rotated 90° counterclockwise around the origin. examine the steps to determine whether she made an error. m (3, –6) is rotated 90° counterclockwise. (x, y) → (–y, x) 1. switch the x- and y-coordinates: (6, –3) 2. multiply the new x-coordinate by –1: (6(–1), –3) 3. simplify: (–6, –3) .

Tom had a total of $220 and he spent $35 on a basketball ticket . what percent of his money did he have left?