How do you solve the system of equations by using substitution: x - 2y = 0 and 2x - 5y = -4?

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Answer 1 · 2016-11-07T18:37:03

#x = 8# and #y = 4#

Step 1) Solve the first equation for #x# while keeping the equation balanced:

#x - 2y = 0#

#x - 2y + 2y = 0 + 2y#

#x = 2y#

Step 2) Substitute #2y# for #x# in the second equation and solve for #y#:

#2(2y) - 5y = -4#

#4y - 5y = -4#

#-y = -4#

#(-y)/-1 = (-4)/-1#

#y = 4#

Step 3) Substitute #4# in the solution for #y# in the first equation.

#x = 2*4#

#x = 8#