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)
Answer:
6 6/7 km/h
Step-by-step explanation:
The relations between speed, time, and distance are ...
time = distance/speed
speed = distance/time
__
So, to find the average speed, we need to know the total distance and the total time. The distances are given, but we need to compute the times.
time jogging = (2 km)/(8 km/h) = 1/4 h
time walking = (2 km)/(6 km/h) = 1/3 h
Then the woman's average speed is ...
average speed = (total distance)/(total time) = (2 km + 2 km)/(1/4 h + 1/3 h)
= (4 km)/(7/12 h) = 48/7 km/h
= 6 6/7 km/h
X = 13
( x + 4) / 51 = (2x - 7) / 57
585 = 45x
585/45 = 45x/45
x = 13
40.2 - 13.7 = 26.5
26.5 / 13.7 * 100 = 193.43
answer
193%