How do you solve the system of equations #x= 7y - 1# and #x = 3y - 9#?

1 Answer
Meave60
Aug 13, 2017

The point of intersection is #(-15,-2)#.

Explanation:

Solve system of equations:

#"Equation 1":# #x=7y-1#

#"Equation 2":# #x=3y-9#

These are linear equations in standard form: #Ax+By=C#. The equations are solved simultaneously by substitution. The values of #x# and #y# represent the point at which the two lines intersect on a graph.

Substitute #7y-1# for #x# in #"Equation 2"# and solve for #y#.

#7y-1=3y-9#

#4y=-8#

#y=-2#

Substitute #-2# for #y# in #"Equation 1"# and solve for #x#.

#x=7(-2)-1#

#x=-14-1#

#x=-15#

The point of intersection is #(-15,-2)#.

http://www.wolframalpha.com/input/?i=solve+system:+x%3D7y-1,+x%3D3y-9

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