# math

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solve with substitution
5x - y=-1
15x=2y

• math -

solve the first equation for y.
5x-y=-1 subtract 5x from both sides
-y=-1-5x divide by -1
y=1+5x

now, plug this answer in for y in the second equation.
15x=2y
15x=2(1+5x)
15x=2+10x
5x=2
x=.4

plug this(x=.4) into the equation for y.
y=1+5x
y=1+5(.4)
y=1+2
y=2

therefore, x=.4 and y=2 or (.4, 2)

• math -

actually that does not work out, plug x and y into original equation...

• math -

actually that does not work out, plug x and y into original equation...
y=1+2
y=3

then it works out

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