Slope intercept form. (8-9); slope=-4/3

What's the difference between: x≥0 and nonnegative integer. ?

Grandpa ernie is shrinking! over the past 4 years his height decreased by a total of 2.4 cm.it decreased by the same amount each year. what was the change in grandpa ernie's height each year

Find the cocordinatse of the point on y axis which is nearest to the point (-2,5)