Iḿ doing a sensitivity analysis in the contants of the constraints

Question

3+4y=40+h
2x+1y=20
2x+3y=60

I need to solve for x ....I know what to do later...I have to solve for y and then I have to solve for h in terms of X and Y..

so I just need you to help me solve for x

thanks

Answer 1

subtract #2 from #3 and you have
2y = 40
y = 20
Looks like x=0

Answer 2

subtract Eq3 fr0m Eq2:
2x+y = 20
2x+3y = 60
Diff:-2y = -40
Y = 20.
In Eq2, replace y with 20 and solve for x:
2x+20 = 20
X = 0.
In Eq1, replace y with 20 and solve for h:
3+4*20 = 40+h
h =