10 now have a good one at the max
Answer:
(9 x 7)/3 + 4
Step-by-step explanation:
9 x 7 = 63
63 divided by 3 is 21.
21 + 4 = 25
Answer:
47.145
Step-by-step explanation:
formula for total surface area of a cylinder is 2×3.143×radius
The first equation is linear:

Divide through by

to get

and notice that the left hand side can be consolidated as a derivative of a product. After doing so, you can integrate both sides and solve for

.
![\dfrac{\mathrm d}{\mathrm dx}\left[\dfrac1xy\right]=\sin x](https://tex.z-dn.net/?f=%5Cdfrac%7B%5Cmathrm%20d%7D%7B%5Cmathrm%20dx%7D%5Cleft%5B%5Cdfrac1xy%5Cright%5D%3D%5Csin%20x)


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The second equation is also linear:

Multiply both sides by

to get

and recall that

, so we can write



- - -
Yet another linear ODE:

Divide through by

, giving


![\dfrac{\mathrm d}{\mathrm dx}[\sec x\,y]=\sec^2x](https://tex.z-dn.net/?f=%5Cdfrac%7B%5Cmathrm%20d%7D%7B%5Cmathrm%20dx%7D%5B%5Csec%20x%5C%2Cy%5D%3D%5Csec%5E2x)



- - -
In case the steps where we multiply or divide through by a certain factor weren't clear enough, those steps follow from the procedure for finding an integrating factor. We start with the linear equation

then rewrite it as

The integrating factor is a function

such that

which requires that

This is a separable ODE, so solving for

we have



and so on.
Answer:
d = -19
Step-by-step explanation:
64 = -3d + 7
Subtracting 7 on both sides,
64-7 = -3d
57 = -3d
Divide both sides by -3,
d = -19