Answer:
Step-by-step explanation:
rate = d / t
rate = 192 / 3
rate = 64 miles / hour
Now you want to know how long it can take to get 448 miles
d = r * t
t = d / r
t = 448/64
t = 7 hours.
You could actually do it using proportions.
192/3 = 448/x Cross multiply
192*x = 448*3
192*x = 1344 Divide by 192
x = 1344/192
x = 7
Do this the way you feel is the best way.
I'd suggest using "elimination by addition and subtraction" here, altho' there are other approaches (such as matrices, substitution, etc.).
Note that if you add the 3rd equation to the second, the x terms cancel out, and you are left with the system
- y + 3z = -2
y + z = -2
-----------------
4z = -4, so z = -1.
Next, multiply the 3rd equation by 2: You'll get -2x + 2y + 2z = -2.
Add this result to the first equation. The 2x terms will cancel, leaving you with the system
2y + 2z = -2
y + z = 4
This would be a good time to subst. -1 for z. We then get:
-2y - 2 = -2. Then y must be 0. y = 0.
Now subst. -1 for z and 0 for y in any of the original equations.
For example, x - (-1) + 3(0) = -2, so x + 1 = -2, or x = -3.
Then a tentative solution is (-3, -1, 0).
It's very important that you ensure that this satisfies all 3 of the originale quations.
Answer:
No Solution
Step-by-step explanation:
-3x+6=-3x-5
+5 +5
-3x+11=-3x
+3 +3
11=0
No Solution
(5,7) (5,4) (7,4) hope that helps
