Slope intercept is y=Mx+b where m is always the slope and b is always your y intercept. The point slope fo is y-y^1=m(x-x^1) where x1 and y1 are a known point and m is the still the slope. X and y is another point on the linear equation
Its a distributive propertyyyyyyy.
No, you only reverse the symbol when the divisor is negative
28 miles
increasing by 40% = original + increase = 100 + 40 = 140% = 1.4
multiplying 20 by 1.4 gives total he will run
miles run = 1.4 × 20 = 28