Intersection of the first two lines:
Multiply the first equation by 4 and the second by 5:
Subtract the two equations:
Plug this value for y in one of the equation, for example the first:
So, the first point of intersection is 
We can find the intersection of the other two lines in the same way: we start with
Use the fact that x and y are the same to rewrite the second equation as
And since x and y are the same, the second point is 
So, we're looking for a line passing through and . We may use the formula to find the equation of a line knowing two of its points, but in this case it is very clear that both points have the same coordinates, so the line must be 
In the attached figure, line 
is light green, line 
is dark green, and their intersection is point A.
Simiarly, line 
is red, line 
is orange, and their intersection is B.
As you can see, the line connecting A and B is the red line itself.
Answer:
1, 1/5, 3/50, 17/25, 21/50 I think
Answer:
e. 10√30
Step-by-step explanation:
In this right triangle geometry, all of the right triangles are similar. This means that the ratio of long side to hypotenuse is the same for all triangles:
x/(10+50) = 50/x
Multiplying by 60x, we have ...
x^2 = 3000
x = 10√30 . . . . . take the square root. Matches choice E.
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<em>Comment on estimating</em>
You're looking for x. Examining the figure, you see that x is the long side of the triangle with hypotenuse 10+50=60, so it will be shorter than that value. x is also the hypotenuse of the triangle with long side 50. So, x will be longer than 50.
The only answer choice with a value between 50 and 60 is choice E.
You don't even need to know how to find x. You only need to know that the hypotenuse is the longest side in a right triangle.
