You can
put this solution on YOUR website!If you plug in the x and y values for b you will find it incorrect.
x=-9,y=7
2x+3y=41 -18+21=39
2x-3y=-13 -18-21=-39
2x+3y=41
2x-3y=-13
Add each column
4x+0=28
divide both sides by 4
x=7
Plug in the value of 7 for x to get the y value
14+3y=41
Subtract 14 from both sides
3y=27
divide both sides by 3
y=9
Plug in the values of x and y in the second equation
(2*7)-(3*9)=-13
-13=-13
You can
put this solution on YOUR website!Determinants can be used to solve a linear system of equations using Cramer’s Rule.
Cramer’s Rule is used for Two Equations in Two Variables, which is what you have: variables x and y.
2x+3y = 41
2x-3y = -13
To find the determinant, we use:
D = 2(-3) - 2(3)
D = -6 -6
D = -12
To find x use:
x = Dx/D
We already know D, right?
We need to find Dx.
We find Dx = 41(-3) - 3(-13)
Dx = -123 + 39
Dx = -84
We can now find x.
So, x = -84/-12
Then x = 7
Lastly, we need to find y.
y = Dy/D
We know D to be -12, right?
To find y, we need to first find Dy.
We can find Dy = 2(-13) - 2(41)
Dy = -26 - 82
Dy = -108
We can now find y.
y = -108/-12
y = 9
The solution to the above system of equations in two variables is the point
(7, 9)
The two equations given to you meet or cross each other at the point (7, 9) and so, this is why that particular point is the solution.
Understood?
The answer is choice (A).