Answer:
$23.87
Step-by-step explanation:
Start by finding out how much one book costs-
$20.46/6=3.41
Then find out how much seven books cost- 3.41 (7)=$23.87
Answer:

Step-by-step explanation:
The slope-intercept form of an equation of a line:

<em>m</em><em> - slope</em>
<em>b</em><em> - y-intercept → (0, b)</em>
The formula of a slope:

From the table we have an y-intercept (0, 9) → b = 9.
Take other point from the table (-6, -1).
Calculate the slope:

Finally:

Answer:
x = 2 cm
y = 2 cm
A(max) = 4 cm²
Step-by-step explanation: See Annex
The right isosceles triangle has two 45° angles and the right angle.
tan 45° = 1 = x / 4 - y or x = 4 - y y = 4 - x
A(r) = x* y
Area of the rectangle as a function of x
A(x) = x * ( 4 - x ) A(x) = 4*x - x²
Tacking derivatives on both sides of the equation:
A´(x) = 4 - 2*x A´(x) = 0 4 - 2*x = 0
2*x = 4
x = 2 cm
And y = 4 - 2 = 2 cm
The rectangle of maximum area result to be a square of side 2 cm
A(max) = 2*2 = 4 cm²
To find out if A(x) has a maximum in the point x = 2
We get the second derivative
A´´(x) = -2 A´´(x) < 0 then A(x) has a maximum at x = 2
Step-by-step explanation:
f(x) = + 8
x = 10?
f(10)= +8
no change