Question

Solve the simultaneous equations 5x+4y = 1 and 3x - 6 y = 2.

Answer 1

Answer:

First equation: x= 1 y= -1

Second equation:  x = 2/3 y = 1/-3

Step-by-step explanation:

Answer 2

x=31​,y=−61​

Put the equations in standard form and then use matrices to solve the system of equations.

5x+4y=1,3x−6y=2

Write the equations in matrix form.

(53​4−6​)(xy​)=(12​)

Left multiply the equation by the inverse matrix of (53​4−6​).

inverse((53​4−6​))(53​4−6​)(xy​)=inverse((53​4−6​))(12​)

The product of a matrix and its inverse is the identity matrix.

(10​01​)(xy​)=inverse((53​4−6​))(12​)

Multiply the matrices on the left hand side of the equal sign.

(xy​)=inverse((53​4−6​))(12​)

For the 2×2 matrix (ac​bd​), the inverse matrix is (ad−bcd​ad−bc−c​​ad−bc−b​ad−bca​​), so the matrix equation can be rewritten as a matrix multiplication problem.

(xy​)=(5(−6)−4×3−6​−5(−6)−4×33​​−5(−6)−4×34​5(−6)−4×35​​)(12​)

Do the arithmetic.

(xy​)=(71​141​​212​−425​​)(12​)

Multiply the matrices.

(xy​)=(71​+212​×2141​−425​×2​)

Do the arithmetic.

(xy​)=(31​−61​​)

Extract the matrix elements x and y.

x=31​,y=−61​