2x-3y=7 and y=3x-7 how do you solve this using subsitution

1 answer:

4 0

$2x-3y = 7~~~....(i)\\\\y = 3x -7~~~....(ii)\\\\\\\text{Substitute}~ y = 3x -7~ \text{in equation (i):}\\\\\\2x-3(3x-7) = 7\\\\\implies 2x -9x + 21 =7\\\\\implies -7x = 7 -21\\\\\implies -7x = -14\\\\\implies x = \dfrac{-14}{-7} = 2\\\\\\\text{Substitute x = 2 in equation (ii):}\\\\y=3(2) -7 = 6 -7 = -1\\\\\\\text{Hence (x,y) =(2,-1)}$

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