I see your last line is : c(x) = 0.9(x^2-10)^2 + 101.1
Let y = x^2, then c(y) = 0.9(y-10)^2 + 101.1
Apparently, c(y) is a parabola, min is 101.1 when y = 10, max is infinity
So let x^2 = 10 -> x = sqrt(10) or -sqrt(10), min is 101.1, max is infinity
Y = mx + b. Use this equation for most linear functions. Enter the information that is given to you.

Multiply the -3 and 4 to get 12.

Now divide the -12 from both sides.

-12 cancels out on the right side and your left with

Now re-enter the info back into the formula.

Then you've got your formula
Answer:
520 m
Step-by-step explanation:
Perimeter is the distance around a shape. To find the perimeter, you add up all the sides.
200 + 60 + 60 + 200 = 520 m
Answer:
4
Step-by-step explanation:
Let x = the number of years
In x years, Mai's mother's age will be: 28 + x
and Mai's age will be: 12 + x
Then, 28 + x = 2(12 + x)
Distribute the 2 28 + x = 24 + 2x
Subtract 24 from each side 4 + x = 2x
Subtract x from each side x = 4
In four years, Mai's mother will be twice Mai's age.
<em>Check:
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28 + 4 = 2(12 + 4)
32 = 2 × 16
32 = 32