Question

{3x+y=10
{X-4y=-1 You must solve for Y

Answer 1

x = 3 and y = 1

Explanation:

Solve the following system:

{3 x + y = 10

x - 4 y = -1

Express the system in matrix form:

(3 | 1

1 | -4)(x

y) = (10

-1)

Solve the system with Cramer's rule:

x = 10 | 1

-1 | -4/3 | 1

1 | -4 and y = 3 | 10

1 | -1/3 | 1

1 | -4

Evaluate the determinant 3 | 1

1 | -4 = -13:

x = 10 | 1

-1 | -4/(-13) and y = 3 | 10

1 | -1/(-13)

Simplify 10 | 1

-1 | -4/(-13):

x = -1/13 10 | 1

-1 | -4 and y = 3 | 10

1 | -1/(-13)

Simplify 3 | 10

1 | -1/(-13):

x = -(10 | 1

-1 | -4)/13 and y = -1/13 3 | 10

1 | -1

Evaluate the determinant 10 | 1

-1 | -4 = -39:

x = (-1)/13×-39 and y = -(3 | 10

1 | -1)/13

(-1)/13 (-39) = 3:

x = 3 and y = -(3 | 10

1 | -1)/13

Evaluate the determinant 3 | 10

1 | -1 = -13:

x = 3 and y = (-1)/13×-13

(-1)/13 (-13) = 1:

Answer: x = 3 and y = 1