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)

Answer 1

wingspan

Answer 2

rowreduce the matrix of the coefficients.

Answer 3

okay so how do i do that @sylbot

Answer 4

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.

Answer 5

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

Answer 6

so would the answer be c

Answer 7

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

Answer 8

is it c @slybot

Answer 9

@sylbot

Answer 10

no it is d.

Answer 11

oh thank u @sylbot

Answer 12

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