How do you solve the system of equations #-2x + 9y = 15# and #x + 7= 4#?

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Answer 1 · 2018-07-30T13:42:17

#color(blue)(x = -3, y = 1#

#-2x + 9y = 15#, Eqn (1)

#x + 7 = 4#

#x = 4 - 7 = -3#

Substituting the value of x in Eqn (1),

#-2 * -3 + 9y = 15#

#6 + 9y = 15#

#9y = 15 - 6 = 9#

#y = 1#

Thus, our solutions are #x=-3# and #y=1#.

Answer 2 · 2018-07-30T20:49:24

#(-3,1)#

In the second equation, we can easily solve for #x# in the second equation by subtracting #7# from both sides. We get

#x=-3#

Now, we can plug this into the first equation to solve for #y#. We get

#-2(-3)+9y=15#

#9y+6=15#

#9y=9=>y=1#

Therefore, our solution is at the point #(-3,1)#

Hope this helps!