Answer:
x=5
Step-by-step explanation:
F(x)=-3x+21,
f(x)=6 = -3x+21
6 = -3x+21
Subtract 21 from each side
6-21 = -3x+21-21
-15 = -3x
Divide each side by -3
-15/-3 = -3x/-3
5 = x
A
rational number is a number which can be expressed as a fraction whose
numerator and denominator are both integers and whose denominator is not equal
to zero. Rational numbers include all integers, fractions, mixed numbers, and
some decimal numbers.
Note : All terminating and repeating decimal
numbers are rational numbers because those numbers can be expressed as a
fraction. On the other hand, a non repeating number and non terminating
decimal, like square root of 2, is an irrational number.
<span>
</span>
Your answer is c ur welcome
Answer:
diameter of the pizza = 21.88 centimeters
Step-by-step explanation:
Given:
C = d^2 – 2d + 447
where
C = cost of the pizza
d = diameter of the pizza
If the pizza costs $12.00, then what is a reasonable estimate for the diameter of the pizza?
12 = d^2 – 2d + 447
d^2 - 2d = 447 - 12
d^2 - 2d = 435
d^2 - 2d - 435 = 0
Solve the quadratic equation using formula
a = 1
b = -2
c = -435
d = -b +or- √b^2 - 4ac / 2a
= -(-2) +or- √(-2)^2 - (4)(1)(-435) / 2(1)
= 2 +or- √4 - (-1740) / 2
= 2 +or- √4 + 1740 / 2
= 2 +or- √1744 / 2
= 2 +or- 4√109 / 2
= 2/2 +or- 4√109/2
= 1 +or- 2√109
d = 1 + 2√109 or d = 1 - 2√109
= 1 + 2(10.44) or d = 1 - 2(10.44)
= 1 + 20.88 or d = 1 - 20.88
d = 21.88 or -19.88
diameter of the pizza = 21.88 centimeters
Therefore, the estimated diameter of the pizza can not be negative. So, diameter of the pizza = 21.88 cm
