exam Maths Puzzle Numerical Ability

using cramers rule, solve

2x - y = 4
3x + y - z = 10
y + z = 3

Read Solution (Total 0)

exam Other Question

How do I answer this problem.
y^4+3y^3-5y^2-15y

I tried to solve it this way but I think that it is wrong.

y^4 + 3y^3 -5y^2-15y
y^3(y+3) -5y(y+3)

=(y+3)(y^3-5y)
y=2x
x-y=4
solve by substituition