Tell whether the lines through the given points are parallel, perpendicular, or neither. (-3,1), (1,9), (-2-9), (-1,-7)
1 answer:
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Answer:
- (x, y) = (8, -1)
- (x, y) = (7, 10.5)
Step-by-step explanation:
1. You can use the expression for y to substitute into the first equation:
2x +4(1/4x -3) = 12
2x +x -12 = 12 . . . . . . eliminate parentheses
3x = 24 . . . . . . . . . . . add 12; next divide by 3
x = 8 . . . . . matches choice C
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2. You can use the expression for y to substitute into the second equation:
x -2(2x -3.5) = -14
-3x +7 = -14 . . . . . . eliminate parentheses
21 = 3x . . . . . . . . . . add 3x+14; next divide by 3
7 = x . . . . . matches the third choice
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When the answer choices are sufficiently different, you only need to find one value to determine which is the correct choice. (If you want to check your work further, you can substitute the other answer value into the two equations to see if it works.)
So, we know both faucets open, can do the whole job in 6minutes
ok, how much has the faster cold water faucet done in 1minute then?
well, let's say the the rate of speed of the cold water faucet is "c", so in 1minute it has done 1/c of the whole work
now, we know the hot water faucet is slower, it takes it 3 times as long, that means is 1/3 the speed of the cold water faucet, so, how much does the hot water faucet do in 1min? well, we know is 1/3 fast as the cold one, the cold one is 1/c, what's 1/3 of 1/c? well, 1/3 * 1/c
now, we know they both added together, can do the whole job in 6 minutes, so in 1minute, they've done 1/6 of the job then
thus
ok, how much has the faster cold water faucet done in 1minute then?
well, let's say the the rate of speed of the cold water faucet is "c", so in 1minute it has done 1/c of the whole work
now, we know the hot water faucet is slower, it takes it 3 times as long, that means is 1/3 the speed of the cold water faucet, so, how much does the hot water faucet do in 1min? well, we know is 1/3 fast as the cold one, the cold one is 1/c, what's 1/3 of 1/c? well, 1/3 * 1/c
now, we know they both added together, can do the whole job in 6 minutes, so in 1minute, they've done 1/6 of the job then
thus