126 . [Sx + 2y = 2 (-3x - y= 0 127. [-3x + y =-9 (x - 2y = -12 128. (6x - 5y = -1 2xty = 13 129 . 3x - y = -7 Jx+y=-1 (4x + 2y = -6 130. Jx+y = -8 (x - y= -5 131. x - y = -6 132. 3x - 2y = 1 133. [-7x + 6y = -10 1-x + 2y = 9 134. [3x + 2y = -3 1x - 6y = 22 -x - 2v = -19 135 . 5x + 2y = 1 136 . [6x + 4y = -4 3x - 4v = -11 -5x - 4y = -7 (-6x - 5y = 8 137 . (x - 2y = -5 138 . 5x - 7y = 29 x+ 3y = -3 139 . 6x - 5v = -75 140. [-x+ 4y = 8 (-x -2y = -13 (3x + 5y = 10 141. [2x - 5y =7 3x - y = 17 142. [5x - 3v= -1 (7x+ )=-4 (2x - ) = 2 143. (13x + 3y = 4 144. [-3x + 5y = -13 145. 3x - 5y = -9 [4x - 3y = 3 (2x+ y = -26 (5x + 2v = 16 146. (2x + 5y = -31 147 4x + 7y = 14 148 5x + 2y = 21 (-2x + 3y =32 149 3x + 8y = -3 7x - 4y = 9 (2x + 5y = -3 150 . [Ilx + 9y = -5 151 . 3x + 8y = 67 (7x + 5y = -1 [2x + 9) = -4 (5x + 3y = 60 152. 13x + 13y = -7 x - y= -3 153. x + by =2 154. x + = =-1 155. (#x -zy =3 Ex - Ly = -2 156 13 * - y = -3 157 . 2x ty=3 (6* + 3y = 9 158. [x - 4v =-1 Ex + Sy = 3 [-3x + 12y = 3 159. [-3x - y = 8 160. (4x + 3y = 2 [3x + 2y = 6 (6x + 2y = -16 (20x + 15y = 10 161. 1-6x -4y = -12 162. 5x - 8y = 12 10x - 16y = 20 163. [-1 1x + 12y = 60 7x - 9y = 16 1-22x + 24y = 90 164. (-21x + 27y = -24159. [-3x - y = 8 160. (4x + 3y = 2 6x + 2y= -16 (20x + 15y = 10 161. [3x + 2y = 6 1-6x - 4y = -12 162 . 5x - 8y = 12 [-1 1x+ 12y = 60 [7x - 9y = 16 10x - 16y = 20 163. (-22x + 24y = 90 164. 1-21x + 27y = -24 This OpenStax book is available for free at http://cnx.org/content/col31130/1.4 Chapter 5 Systems of Linear Equations 627 5x - 3y = 15 (2x + 4y = 7 165. ly= Ex-2 166 . 1 = - 2x-4 Solve Applications of Systems of Equations by Elimination In the following exercises, translate to a system of equations and solve. 167. The sum of two numbers is 168. The sum of two numbers is 169. The sum of two numbers is 65. Their difference is 25. Find the 37. Their difference is 9. Find the -27. Their difference is -59. Find numbers. numbers. the numbers. 170. The sum of two numbers is 171. Andrea is buying some new 172. Peter is buying office -45. Their difference is -89. Find shirts and sweaters. She is able to supplies. He is able to buy 3 the numbers. buy 3 shirts and 2 sweaters for packages of paper and 4 staplers $114 or she is able to buy 2 shirts for $40 or he is able to buy 5 and 4 sweaters for $164. How packages of paper and 6 staplers much does a shirt cost? How for $62. How much does a much does a sweater cost? package of paper cost? How much does a stapler cost? 173. The total amount of sodium in 174. The total number of calories 2 hot dogs and 3 cups of cottage in 2 hot dogs and 3 cups of cheese is 4720 mg. The total cottage cheese is 960 calories. The amount of sodium in 5 hot dogs total number of calories in 5 hot and 2 cups of cottage cheese is dogs and 2 cups of cottage cheese 6300 mg. How much sodium is in a is 1190 calories. How many hot dog? How much sodium is in a calories are in a hot dog? How cup of cottage cheese? many calories are in a cup of cottage cheese?167. The sum of two numbers is 168. The sum of two numbers is 169. The sum of two numbers is 65. Their difference is 25. Find the 37. Their difference is 9. Find the -27. Their difference is -59. Find numbers. numbers. the numbers. 170. The sum of two numbers is 171. Andrea is buying some new 172. Peter is buying office ir difference is -89. Find shirts and sweaters. She is able to supplies. He is able to buy 3 the numbers. buy 3 shirts and 2 sweaters for packages of paper and 4 staplers $114 or she is able to buy 2 shirts for $40 or he is able to buy 5 and 4 sweaters for $164. How packages of paper and 6 staplers much does a shirt cost? How for $62. How much does a much does a swe package of paper cost? How much does a stapler cost? 173. The total amount of sodium in 174. The total number of calories Home 2 hot dogs and 3 cups of cottage in 2 hot dogs and 3 cups of Course cheese is 4720 mg. The total cottage cheese is 960 calories. The amount of sodium in 5 hot dogs total number of calories in 5 hot and 2 cups of cottage cheese is dogs and 2 cups of cottage cheese C 6300 mg. How much sodium is in a is 1190 calories. How many hot dog? How much sodium is in a calories are in a hot dog? How cup of cottage cheese? many calories are in a cup of cottage cheese? Choose the Most Convenient Method to Solve a System of Linear Equations In the following exercises, decide whether it would be more convenient to solve the system of equations by substitution or elimination. 175. 176. 177. @ (8x - 15y = -32 @ Jy = 7x -5 (y = 4x + 9 (6x + 3y = -5 3x - 2y = 16 (5x - 2y = -21 [x = 4y -3 [12x - 5y = -42 9x - 4y = 24 (4x - 2y =-6 (3x + 7y= -15 (3x + 5y = -14 178. @ (14x - 15y = -30 (7x + 2y = 10 [x =9y - 11 (2x - 7y = -27 Everyday Math 179. Norris can row 3 miles upstream against the 180. Josie wants to make 10 pounds of trail mix using current in 1 hour, the same amount of time it takes him nuts and raisins, and she wants the total cost of the to row 5 miles downstream, with the current. Solve the trail mix to be $54. Nuts cost $6 per pound and raisins system. Ir- c = 3 cost $3 per pound. Solve the system Intr = 10 Irto =5 16n + 3r = 54 @ for r, his rowing speed in still water. to find n, the number of pounds of nuts, and r, the Then solve for c, the speed of the river number of pounds of raisins she should use. current