Answer:
just follow the rules
Step-by-step explanation:
Cramer's rule applies to the case where the coefficient determinant is nonzero. ... A simple example where all determinants vanish (equal zero) but the system is still incompatible is the 3×3 system x+y+z=1, x+y+z=2, x+y+z=3.
Write the system as a matrix equation. ...
Create the inverse of the coefficient matrix out of the matrix equation. ...
Multiply the inverse of the coefficient matrix in the front on both sides of the equation. ...
Cancel the matrix on the left and multiply the matrices on the right.
Answer:
The first problem has no real solution
Step-by-step explanation:
I=1.5m
m+1.5m=20
2.5m=20
m=8
20-8=12
Isobel worked 12 hours.
