The derivative of f(x) at x=3 is 2x=6 approaching from the left side (apply power rule to y=x^2). The derivative of f(x) at x=3 is m approaching from the right side. In order for the function to be differentiable, the limit of derivative at x=3 must be the same approaching from both sides, so m=6. Then, x^2=mx+b at x=3, plug in m=6, 9=18+b, so b=-9.
Maybe a yard or a foot of wood or smt i’m sorry if i’m not that helpful but i tried stay safe guysss :))
I believe the answer is 11ft
I am setting the week hourly rate to x, and the weekend to y. Here is how the equation is set up:
13x + 14y = $250.90
15x + 8y = $204.70
This is a system of equations, and we can solve it by multiplying the top equation by 4, and the bottom equation by -7. Now it equals:
52x + 56y = $1003.60
-105x - 56y = -$1432.90
Now we add these two equations together to get:
-53x = -$429.30 --> 53x = $429.30 --> (divide both sides by 53) x = 8.10. This is how much she makes per hour on a week day.
Now we can plug in our answer for x to find y. I am going to use the first equation, but you could use either.
$105.30 + 14y = $250.90. Subtract $105.30 from both sides --> 14y = $145.60 divide by 14 --> y = $10.40
Now we know that she makes $8.10 per hour on the week days, and $10.40 per hour on the weekends. Subtracting 8.1 from 10.4, we figure out that she makes $2.30 more per hour on the weekends than week days.
Is the same as the one you just did.
keep in mind that, going against the current, the current's speed erodes speed from your regular speed, whilst if you're going with the current, the current's speed adds to it.
now, in this case, you row 5mph, going upstream you're only doing 3mph, whatever happened to the other 2mph? well, the current speed eroded them, meaning the speed of the river is 2mph.
now, going downstream with the current, your regular speed is 5mph, and the current is 2mph, since the current adds to yours, then you're going 5 + 2, mph.
