Answer:
x=11
Step-by-step explanation:
6x-3(x+8)=9
Using the distributive property, we can turn 6x-3(x+8)=9 into 6x-3x-24=9, which simplifies to 3x-24=9 by combining like terms. Now, if we add 24 to both sides, we get 3x=33. By dividing both sides by 3, we get x=11.
Check:
66-3*19=9
66-57 does in fact equal 9.
Givens
<em><u>Slower car</u></em>
r = r
t = 12 hours
d = ?
<em><u>Faster car</u></em>
r = r + 20
t = 8 hours
d = ?
It doesn't matter what the exact distance is. You just have to know that the 2 distances are equal ie going to the mountains from his home is the same distance as going from the mountains to his home.
d = r * t
r * 12 hours = (r + 20)* 8 hours. Remove the brackets on the right
r*12 = 8r + 20*8
r*12 = 8*r + 160
r*12 - 8r = 8r - 8r + 160
4r = 160
r = 40 miles / hour
=================
Slower Ride determines the distance.
d = r*t
d = 40 * 12
d = 480
Check
Use the faster rate (r + 20) = 40 + 20 = 60 mph
60 * 8 = 480. Both distances work out to be the same.
