7. solve 2x - y = 7 for y. then find the value of y when x = -1,0, and 1.

Step-by-step explanation:

We want to solve 2x - y = 7 for y.  Start by changing the signs of all terms, obtaining -2x + y = -7.  Now add 2x to both sides, obtaining  y = 2x - 7.

Now evaluate this at x = -1:             y(-1) = 2(-1) - 7 = -2 - 7 = -9

Now evaluate this at x = 0:             y(0) = 2(0) - 7 = 0 - 7 = -7

Now evaluate this at x = 1:             y(1) = 2(1) - 7  = 2 - 7 = -5

for finding the midpoint of any given 2 pair of points simply add the respective x coordinates with other x coordinate and the y coordinate with other y coordinate and divide them by 2

in your question it will be :

(3+1)/2 for the x coordinate of mid point i.e 2

[8+(-4)]/2 for the y coordinate of midpoint i.e 2

so coordinates of mid point of points (3,8) and (1,-4) will be (2,2)

your answer is 125y5