69.75 x 0.05 = $3.49 discount
$69.75 - $3.49 = $66.26 discounted price with tax
66.26 x 0.18 = $11.93 tip
Discounted price with tax + tip
66.26 + 11.93 = 78.19
The slope-intercept form is:
y = mx + b
where m = slope, and b = y-intercept.
You need a slope of 1, so m = 1.
You need a y-intercept of -1, so b = -1.
Replace m with 1 and b with -1 in the slope intercept form to get
y = 1x + (-1)
which simplifies to
y = x - 1
Increase.
1/4 can be translated to 25%
1/2 can be translated to 50%
25% to 50% is an increase.
