Question #625d7 Algebra Systems of Equations and Inequalities Linear Systems with Addition or Subtraction 1 Answer Eddie Jan 22, 2017 #x,y = 2,1# Explanation: #A: qquad color(red)(3)x + 7y = 13 # #B: qquad color{red}{-9}x + 3y = -15 # #3 times A: qquad 9x + 21y = 39 # #(3 times A) + B implies qquad color(green)(9x + 21y) + color(blue)((-9x + 3y)) = color(green)(39) + color(blue)((-15))# OR: # 24y = 24 implies y = 1# plug back into A: #3x + 7(1) = 13 implies x = 2# Answer link Related questions What if the elimination method results in 0=0? How do you use the addition and subtraction method to solve a linear system? Can any system be solved using the addition and subtraction method? When is the addition and subtraction method easier to use? How do you solve #-x-6y=-18# and #x-6y=-6# using the addition and subtraction method? How do you solve #5x-3y=-14# and #x-3y=2# using elimination? Do you need to add or subtract the equations #5x+7y=-31# and #5x-9y=17# to solve the system? How do you solve the system of equations #3y-4x=-33# and #5x-3y=40.5#? What is the solution to the system #x+y=2# and #x-y=6#? What is the common point of #x+2y=6# and #x+y=2#? See all questions in Linear Systems with Addition or Subtraction Impact of this question 1210 views around the world You can reuse this answer Creative Commons License