When you multiply the same number with different exponents together, you add the exponents together.
3^2 + 3^x = 3^7
Adding the two together you have 3^(2 + x = 7)
Solve for x: 2 + x = 7
Subtract 2 from both sides:
x = 5
Answer:
Step-by-step explanation:
Remark
The two trains are travelling towards each other. That means that their total distance = 912 km. Neither one has gone that distance by itself. The effect this has on the question is that you add the two rates multiplied by time.
Givens
r1 = x
r2 = x + 12
t = 3 hours
d = 912 km
Equation
d = r * t
r1 * t + r2 * t = 912
Solution
3x + 3*(x + 12) = 912 Remove the brackets
3x + 3x + 36 = 912 Combine like terms
6x + 36 = 912 Subtract 36 from both sides
<u> -36 -36</u>
6x = 876 Divide both sides by 6
6x/6 = 876/6
x = 146 km/h
Answer
Slow train = 146 km/hr
Fast train = 146 + 12 = 158 km/hr
Y=(1)/(3)x-9 that’s the answer
