A/3=7/10
21=10a
a=2.1
100a=100*2.1=210
Split it up
3x^2+12x-5x-20
group
(3x^2+12x)+(-5x-20)
factor
(3x)(x+4)+(-5)(x+4)
undistribute (x+4) like ab+ac=a(b+c)
(3x-5)(x+4)
Flat rate=y intercept
rate per mile=slope
y=3x+10 would be it
1.
3 is the value of the slope (3 dollars per mile)
2.
y intercept is (0,10)
3.
22 miles
y=3(22)+10
y=66+10
y=76
$76