How do you solve the system of equations #f(x)=x+4# and #g(x)=-4x+9# by graphing?

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Answer 1 · 2017-12-05T03:36:20

The solution is the ordered pair where the lines intersect.

In this case, that is (1,5)

The point where the lines cross is the only point whose values satisfy both equations.

In this case, the point (1,5) is the only point found on both lines.

#f(x) = x + 4#
#color(white)(. )# # 5 = 1 + 4#

#f(x) = - 4 x + 9#
#color(white)(. )# #5 = - 4(1) +9#

~ ~ ~ ~ ~ ~ ~

to find this point, graph both of the lines and see where they intersect.

You can see this solution by entering both equations here, and letting the computer draw the lines.