Answer:
7
Explanation:
When finding the system determinant you take both of the x-coefficients and put them in the 1st column and then the y-coefficients in the 2nd column.
Always start with the first equation when ordering this
2x - y = 5
x + 3y = 7
2x and 1x are your x-coefficients
-1y and 3y are your y-coefficients
Column 1 is both of the x-coefficients and the number at the top of the column will always be from the first equation.
Column 2 is both of the y-coefficients and the number at the top of the column will always be from the first equation.
C1 = Column 1
C2 = Column 2
C1 C2
Row 1 [2 -1]
Row 2 [1 3]
First multiply Column 1 ,Row 1 by Column 2 ,Row 2
2 × 3 = 6
And then cross multiply again with the two remainding numbers 1 and 1
-1 × 1 = -1
After cross multiplying the columns you take the number that you got by multiplying Column 1, Row 1 and Column 2, Row 2 (6) and you will subtract it by the answer you got from multiplying Column 1, Row 2 and Column 2, Row 1 (-1).
Then you will take your number from the first equation and subract it by the number you got in the second equation
6 - (-1) = 7
Remember that when subtracting the order matters and if you do not subtract in this order you will get a different answer.
