Answer:
y=3
Step-by-step explanation:
Lets set 4 points A(11,[tex]y_{1}[/tex]), B(2,0), C(7,5), D(-2,2)
So first we need to find a line that passes through points C and D
[tex]\left \{ {{a*7+b=5} \atop {a*(-2)+b=2}} \right.[/tex]
We subtract these two
9a=3
a=3/9
a=1/3
b=2+2*[tex]\frac{1}{3}[/tex]
b=8/3
So the line passing through C and D is [tex]\frac{1}{3}x+\frac{8}{3}=y[/tex]
We do the same for the line passing through A and B
[tex]\left \{ {{a*11+b=y_{1}} \atop {a*2+b=0}} \right.[/tex]
9*a+y
Line AB and line CD will be paraller if [tex]a_{1}= a_{2}[/tex]
So from that we know that a=1/3
So 9*(1/3)=3=y
