Question 483861
the slope of 1st line is 1/2, since
2y=x-7
y=x/2-7/2.

Therefore, the slope of 2nd line is -2.

m:slope
(x1,y1): (-3,4)
the line we're looking for is: 
m=(y-y1)/(x-x1)
-2=(y-4)/(x+3)
y=-2x-2
Then, x-intercept of this line: where y=0, x=-1