Answer:
y-30 = 3(x-1)
Step-by-step explanation:
Point-slope form of an equation is
y-y1 = m(x-x1) where (x1,y1 ) is a point and m is the slope
We know on day 1 they exercised 30 minutes (1,30) where x is the number of days and y is the minutes. The rate increased 3 minutes each day so m = 3
y-30 = 3(x-1)
lets solve for x
flip the equation
add-4 to both sides
divide both sides by 3
x=1/3y+-4/3
The equation of a line is:
y = mx + c
The m is the gradient of the line, and the c is the y-intercept of the line
That means that the y-intercept of [y = -4x + 3] is 3
and the y-intercept of [y = -4x + 4] is 4
So the distance between the two y-intercepts is:
4 - 3 = <u>1</u>
to do it in mental math: you can ignore the zeroes in 400 for now.
4*14 = 4*10 + 4*4 = 40 + 16 = 56
now add the zeroes back on: 5600m
