D(7, 3), E(8, 1), and F(4, -1)
We calculate the squared distances between the points:
Since 
we have a right triangle with hypotenuse DF.
For elimination, multiply one whole equation by negative one (-1), then add or subtract according to your signs. After that, it will be a one-step equation.
3x + 4y = 19 3x + 4y = 19 3x + 4y = 19 -2y = -14 y = 7
3x + 6y = 33 -1 (3x + 6y = 33) -3x - 6y = -33 -14 / -2
Then you would go back and substitute the value of (y) back into either equation and then solve for the remaining variable (x). Finally, use both values to make an ordered pair.
3x + 4y = 19 3x = -9 x = -3 (-3 , 7)
3x + 4(7) = 19 (-9 / 3)
3x + 28 = 19
Good Luck
The answer is B because you multiply 2500 by 7 and then add it to 50,000
