Y=-x+7
y=2x-2
and then the second problem is
y-1=2x
y+2x=5
they are substitutional problems! show work it's greatly appreciated!

Question 1:
y=-x+7
y=2x-2

(-x+7)=2x-2
-x+7+x=2x-2+x
7=2x-2+x
7+2=2x-2+x+2
9=3x
9/3=3x/3
3=x

y=-x+7
y=-(3)+7
y=4

Question 2:
y-1=2x
y+2x=5

y-1=2x
y-1+1=2x+1
y=2x

(2x+1)+2x=5
2x+1+2x=5
4x+1=5
4x+1-1=5-1
4x=4
4x/4=4/4
x=1

y-1=2(1)
y-1+1=2+1
y=3

x=1 y=3

4hours and 40 mins she would be 120 meters high