To solve this you do 25-7=18 and do 18÷6=3, so my number is 3. To check if this is correct you do 3×6=18 and 18+7=25
6x + 2y = 24....subtract 6x from both sides
2y = -6x + 24...now divide both sides by 2
y = -6/2x + 24/2...now reduce
y = -3x + 12 <=== slope intercept form of y = mx + b
Nathan didn't talk on the phone. I think there's a typo in the question
The function would be f(x) = 40x + 4.
It's plus 4 because it starts counting after the 4 kilometers already happened.
It's 40x because that's the rate of change (km/h) and the x represents the hours.
f(x) basically means y, but in functions you use f(x).
Hope this helps :)