Using Cramer's law to solve the equation// 2x+5y=40 4x+8y=30
① Multiply by 2 - 2 to get 2Y = 50
The solution is y = 25
x=-42.5
What is Kramer's rule for solving equations
That is, if the determinant of a system of linear equations is not equal to zero, the system of equations must have a unique solution