Find and equation of the line containing the given pairs -3 -7and -9 -5?

Answer 1

y = -x/3 - 8

Using the standard equation for a straight line , y = mx + c

Then -7 = -3m + c, therefore 3m = c + 7 : multiplying by 3 leads to 9m = 3c + 21

and -5 = -9m + c, therefore 9m = c + 5

As 9m = 3c + 21 = c + 5, then 2c = -16, thus c = -8

Substituting for c in (say) the equation 3m = c + 7 gives 3m = -8 + 7 = -1, then m = -1/3.

Then y = mx + c becomes y = -x/3 - 8.