The answer is 600 because of the miles
9514 1404 393
Answer:
C, A, A
Step-by-step explanation:
In general, you ...
- identify the coefficients of one of the variables
- swap them, and negate one of them
- multiply the corresponding equations by the "adjusted" coefficients.
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In problem 1, the x-coefficients are 8 and 2. A common factor of 2 can be removed so that we're dealing with the numbers 4 and 1. Assuming we want to multiply one of the equations by 1, leaving it unchanged, the value we want to multiply by will be -4. After we swap the coefficients, that multiplier is associated with equation 2:
multiply equation 2 by -4 . . . (eliminates x)
Likewise, the y-coefficients in problem 1 are -1 and 3. Again, if we want to multiply one of the equations by 1, leaving it unchanged, the coefficient we will change the sign of is -1 (becomes 1). After we swap the coefficients, the multiplier 3 is associated with equation 1:
multiply equation 1 by 3 . . . (eliminates y)
These two choices are B and A, respectively, so the one that does NOT work for problem 1 is choice C, as indicated below.
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The other problems are worked in a similar fashion.
Answer:
The answer is below
Step-by-step explanation:
a) Let x represent the time taken to drive to see the relatives and let d be the distance travelled to go, hence:
60 mi/h = d/x
d = 60x
When returning, they still travelled a distance d, since the return trip takes 1 h longer than the trip there, therefore:
40 mi/h = d/(x+1)
d = 40(x + 1) = 40x + 40
Equating both equations:
60x = 40x + 40
60x - 40x = 40
20x = 40
x = 40/20
x = 2 h
The time taken to drive there = x = 2 hours
b) The time taken for return trip = x + 1 = 2 + 1 = 3 hours
c) The distance d = 60x = 60(2) = 120 miles
The total distance to and fro = 2d = 2(120) = 240 miles
The total time to and fro = 2 h + 3 h = 5 h
Average speed = total distance / total time = 240 miles / 5 h = 48 mi/h
Answer:
<h2>(-3) + 4x + 2 + 2x + 2x = 8x - 1</h2>
Step-by-step explanation:
(-3) + 4x + 2 + 2x + 2x <em>combine like terms</em>
= (4x + 2x + 2x) + (-3 + 2)
= 8x - 1