4x + 3y = 12
3y = -4x + 12
y = -4/3x + 4........so the slope (or gradient) is -4/3...because in y = mx + b form, the slope(gradient) is in the m position and the y int is in the b position....so if u wanted to know the y axis, it would be (0,4)
the x intercept (where the line crosses the x axis) can be found by subbing in 0 for y in the original equation or the slope intercept equation, and solving for x.
4x + 3(0) = 12
4x = 12
x = 12/4 = 3....so the x intercept is (3,0)
The slope of the line is -4
Can u post a picture so I can better understand the question?
Explanation: more details.
Since he drives 60 miles per hour we'll divide 272 by 60
272/60=4.5
it will take 4.5 hours
I hope I've helped!