Answer:

and x=4
Step-by-step explanation:
We are given that a curve

We have to find the equation of tangent at point (4,2) on the given curve.
Let y=f(x)
Differentiate w.r.t x

By using the formula 
Substitute x=4
Slope of tangent

In given question


By comparing we get a=4
Point-slope form

Using the formula
The equation of tangent at point (4,2)




If b was 3 a will be 6 because 2*3=6
and for the second part b will be 3.5 because 2*3.5=7
You divide 2930 by 34 to get about 86.1765
(I think)
When you do the multiplication you can notice that 10, 20, 30, 40 all have 0's at the end.
So that means 10 *20*30*40 = 1*2*3*4*10000 = 24*10000 = 240,000
Answer: ![(-\infty, -4]](https://tex.z-dn.net/?f=%28-%5Cinfty%2C%20-4%5D)
Curved parenthesis at negative infinity
Square bracket at -4
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Work Shown:

The last inequality shown above is the same as saying 
Converting this to interval notation leads to the final answer of ![(-\infty , -4]](https://tex.z-dn.net/?f=%28-%5Cinfty%20%2C%20-4%5D)
Note the use of a square bracket at -4 to include this endpoint. We can never include either infinity, so we always use a parenthesis for either infinity.