Since if he gets the driveway done in 20 minutes he gets 1/20th of the driveway done in 1 minute (if x=20 then x/20=1 by dividing both sides by 20) and if his brother gets 1/12th of the driveway done in one minute, then if t represents the time it takes to shovel the driveway, t/20+t/12=1 driveway shoveled as 1/20+1/12=amount they can do in 1 minute, so t/20+t/12 is how much they can do in t minutes. Multiplying both sides by 20*12=240, we get 12t+20t=32t=240. Dividing both sides by 32, we get 240/32=7.5 minutes to shovel the driveway.
The first set:
3x + 2y = 2 ---1)
5x + 4y = 6 ---2)
From 1), multiply all by 2, 6x + 4y = 4 ---3)
3) - 2),
6x + 4y - (5x + 4y) = 6 - 4
6x + 4y - 5x - 4y = 2
x = 2
Sub in x = 2 into 1),
3(2) + 2y = 2
2y = -4
y = -2
(2 , -2)
The second set:
3x + 2y = 2 ---1)
11x + 8y = 10 ---2)
From 1), multiply all by 4, 12x + 8y = 8 ---3)
3) - 2),
12x + 8y - (11x + 8y) = 8 - 10
12x + 8y - 11x - 8y = -2
x = -2
From this x value alone, we can tell that these two linear systems do NOT have the same solution as they meet at different coordinates.
Hope this helped! Ask me if there's any working from here that you don't understand! :)
Answer:
7
Step-by-step explanation:
3 * 7 = 21
21 - 7 = 14
7*2 =14
No the answer to the solution would be 7
Answer:
x^3-7
Step-by-step explanation:
The cube of a number means that it is to the power of 3 and 7 is subtracted is just the number cubed and then minus 7.
