Answer:
x is 35
Step-by-step explanation:
First do 180 -40 and get 140. Then add 3x plus x to get 4x because they are the same value/ Do 140/ 4x and get 35. X equals 35.
There would be 12 litres in the tub after 4 minutes
Answer:
90% of the questions she answered correctly
Step-by-step explanation:
%age = 81/90 * 100= 90 % correctness
Answer:
Part 1)
See Below.
Part 2)

Step-by-step explanation:
Part 1)
The linear approximation <em>L</em> for a function <em>f</em> at the point <em>x</em> = <em>a</em> is given by:

We want to verify that the expression:

Is the linear approximation for the function:

At <em>x</em> = 0.
So, find f'(x). We can use the chain rule:

Simplify. Hence:

Then the slope of the linear approximation at <em>x</em> = 0 will be:

And the value of the function at <em>x</em> = 0 is:

Thus, the linear approximation will be:

Hence verified.
Part B)
We want to determine the values of <em>x</em> for which the linear approximation <em>L</em> is accurate to within 0.1.
In other words:

By definition:

Therefore:

We can solve this by using a graphing calculator. Please refer to the graph shown below.
We can see that the inequality is true (i.e. the graph is between <em>y</em> = 0.1 and <em>y</em> = -0.1) for <em>x</em> values between -0.179 and -0.178 as well as -0.010 and 0.012.
In interval notation:
