Use substitution to determine if the ordered pair is an element of the solution set of the system of equations.
(4,-2) {x+y=2
{y+2x=5

Question

Use substitution to determine if the ordered pair is an element of the solution set of the system of equations.
(4,-2) {x+y=2
           {y+2x=5

anonymous · Answer

you can just plug them in?

anonymous · Answer

that's what I did,but my teacher said I was wrong...

anonymous · Answer

(A) x+y=2
(B) y+2x=5
x=2-y (from equation A) take this sub into equa B
y+2(2-y)=5
y+4-2y=5
-y+4=5
y=-1
x=3

anonymous · Answer

hence (4,-2) is not a solution since it is not equal to (3,-1) and nor is it a multiple of (3,-1)

anonymous · Answer

oh okay thank you , can you help me with a similar one please?