exam Maths Puzzle Numerical Ability

Hi, can someone help we this question using echelon?

4x- y + 3z= -2
3x+ 5y - z= 15
-2x+ y + 4z= 14

Read Solution (Total 0)

exam Other Question

A bricklayer and an eectrician together 90 hours working on a new house. If the bricklayer earns $12 per hour, the electrician earns $16 per hour, and the wner pays them a total of $1350 for their work, how many hours does each worker spend on the house? I need to find the inverse p^-1(x) of the function p(x)= -e^x-3^ + 4

I got to this point and couldn't decide how to solve it:

ln(4-x) = y-3

I know im almost there..could