Question

Use cramer's rule to solve the system of equations. write your answer as an ordered pair.
{x-2y=-9
3x+y=1

Answer 1

1 -2
3 1
that's the regular matrix
switch the variable you want to solve for with the answers, so if you were to solve for x you would switch it to
-9 -2
1 1

Answer 2

and then you solve the matrix

Answer 3

how would you solve it though, because every time I try to solve it as soon as I get it to that point I mess up?

Answer 4

-9*1-1*(-2)
-9-(-2)
-7 so x=-7

Answer 5

well if i remember correctly that's how you solve a matrix, i could be wrong though.

Answer 6

So would you do the same thing for y?

Answer 7

yeah for y you would do
1 -9
3 1

Answer 8

so it would be
1-(-27)=28 right?

Answer 9

yes

Answer 10

you should just plug the answers back into the original equation to make sure because i might be wrong

Answer 11

yeah, it doesn't come out right..this is what keeps happening to me

Answer 12

@sakeene831 the answer is x=-1 y=4

Answer 13

thank you!

Answer 14

forgot to get the determinant of the equation first which is 7 after you get the determinant you replace x with -9 and 1 or y with -9 and 1 and then you divide the answer with the determinant which is 7
so in the end it's x=-7/7 and y=28/7