The best method for solving # 1 is substitution x - 0.9y = 4.5......x = 0.9y + 4.5 now sub 0.9y + 4.5 in for x in the other equation 1.5(0.9y + 4.5) - 1.9y = -29 ----distribute through the parenthesis 1.35y + 6.75 - 1.9y = -29 1.35y - 1.9y = -29 - 6.75 -0.55y = -35.75 y = -35.75 / -0.55 y = 65
x - 0.9y = 4.5 x - 0.9(65) = 4.5 x - 58.5 = 4.5 x = 4.5 + 58.5 x = 63 solution is (63,65)
The best method for solving # 4 is by elimination 14x + 7y = 217 14x + 3y = 189...multiply by -1 ----------------- 14x + 7y = 217 -14x - 3y = -189 (result of multiplying by -1) ----------------add 4y = 28 y = 28/4 y = 7
