Which of the following points is a solution to the following system of equations?
x + y = 1
3x – y = 3
a. (3, 0)
b.(5, –1)
c.(1, 4)
d.(1, 0)

Question

Which of the following points is a solution to the following system of equations?
x + y = 1
3x – y = 3
a. (3, 0)
b.(5, –1)
c.(1, 4)
d.(1, 0)

anonymous · Answer

wingspan

anonymous · Answer

rowreduce the matrix of the coefficients.

anonymous · Answer

okay so how do i do that @sylbot

anonymous · Answer

use a calculator. type out matrix with coefficients. Use row reduce command. The answer will simplify one of the coefficients to 0, and one to your answer for that coefficient. 

OR you could use normal algebra and add the two equations to eliminate y, and get 4x=4.

anonymous · Answer

thus x=1. Plug this back into either equation and solve for y.

anonymous · Answer

so would the answer be c

anonymous · Answer

but the rowreduce method is very powerful if you have more than 2 equations because it becomes a huge pain to do by hand.

anonymous · Answer

is it c  @slybot

anonymous · Answer

@sylbot

anonymous · Answer

no it is d.

anonymous · Answer

oh thank u @sylbot

anonymous · Answer

you plug 1 into x. 
take either equation, ill take the the first 
1+y=1
so y equals 0