Question

4 by X + 3 by Y = 15 2 by x + 4 by y = 3 crammer​

Answer 1

Step-by-step explanation:

Given equations are x+y=15,x−y=3

Using Cramer's rule, find the determinant of the coefficient matrix,

D=

∣

∣

∣

∣

∣

∣

1

1

1

−1

∣

∣

∣

∣

∣

∣

=1×−1−(1×1) =−1−1 =−2

Secondly, find the determinant of x coefficient matrix,

D

x

=

∣

∣

∣

∣

∣

∣

15

3

1

−1

∣

∣

∣

∣

∣

∣

=15×−1−(3×1) =−15−3=−18

Similarly, find the determinant of y coefficient matrix,

D

y

=

∣

∣

∣

∣

∣

∣

1

1

15

3

∣

∣

∣

∣

∣

∣

=1×3−(1×15) =3−15=−12

Applying Cramer's rule,

x=

D

D

x

∴x=

−2

−18

=9

y=

D

D

y

∴y=

−2

−12

=6

Therefore, x=9,y=6