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3 years ago

F(x) =5x^2-20x+3 how to find minimum

Mathematics

1 answer:

Leya [2.2K]3 years ago

3 0

Answer:

(2,-17) should be the minimum.

Step-by-step explanation:

The minimum of a quadratic function occurs at $x=-\frac{b}{2a}$ . If a is positive, the minimum value of the function is $f(-\frac{b}{2a})$

$f_{min}x=ax^2+bx+c$ occurs at $x=-\frac{b}{2a}$

Find the value of $x=-\frac{b}{2a}$

x = 2

evaluate f(2).

replace the variable x with 2 in the expression.

$f(2)=5(2)^2-20(2)+3$

simplify the result.

$f(2)=5(4)-20(2)+3$

$f(2)=20-40+3$

$f(2)=-17$

The final answer is -17

Use the x and y values to find where the minimum occurs.

HOPE THIS HELPS!

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Devon and his friends bought strawberry wafers for $3 per packet and chocolate wafers for $1 per packet at a carnival. They spen

Irina-Kira [14]

Hi there!

PART A:
The system of equations we would use would be:
x + y = 22 (amount of items)
3x + 1y = 30 (cost)

Variables:
x = the amount of strawberry wafers bought at the price of $3
y = the amount of chocolate wafers bought at the price of $1

PART B:
To solve, we'll use substitution because we can easily isolate a variable using the first equation.

Work:
x + y = 22 (first equation)
y = 22 - x (isolating a variable)
3x + 1y = 30 (second equation)
3x + (22 - x) = 30 (substituting into the second equation)
2x + 22 = 30 (simplifying)
2x = 8 (subtracting)
x = 4 strawberry wafers
4 + y = 22 (substituting x into the first equation to solve for y)
y = 18 chocolate wafers

ANSWER:
They bought 4 strawberry wafers and 18 chocolate wafers.

Hope this helps!! :)
If there's anything else that I can help you with, please let me know!

8 0

3 years ago

Write the number, 81.402 in expanded form using powers of ten.

stich3 [128]

Answer:

the answer is 81.402 in expanded form using the powers of ten = (8 x 10^1) + (1 x 10^0) + (4/10^1) + (0/10^2) + (2/10^3)

Step-by-step explanation:

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3 years ago

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Norma-Jean [14]

Answer:

129 = x

Step-by-step explanation:

The exterior angle is equal to the sum of the opposite interior angles

47+82 = x

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6 0

3 years ago

Read 2 more answers

A rectangular swimming pool is bordered by a concrete patio. the width of the patio is the same on every side. the area of the s

andre [41]

Answer:

$x = \frac{1}{4}\left(-(l + w) + \sqrt{l^2 + 6lw + w^2} \right)$

where

l = length of the pool (w/o the patio)
w = width of the pool (w/o the patio)

Explanation:

Let

x = width of the patio
l = length of the pool (w/o the patio)
w = width of the pool (w/o the patio)

Since the pool is bordered by a complete patio,

Length of the pool (with the patio)
= (length of the pool (w/o the patio)) + 2*(width of the patio)
Length of the pool (with the patio) = l + 2x

Width of the pool (with the patio)
= (width of the pool (w/o the patio)) + 2*(width of the patio)
Width of the pool (with the patio) = w + 2x

Note that

Area of the pool (w/o the patio)
= (length of the pool (w/o the patio))(width of the pool (w/o the patio))
Area of the pool (w/o the patio) = lw

Area of the pool (with the patio)
= (length of the pool (w/o the patio))(width of the pool (w/o the patio))
= (l + 2x)(w + 2x)
= w(l + 2x) + 2x(l + 2x)
= lw + 2xw + 2xl + 4x²
Area of the pool (with the patio) = 4x² + 2x(l + w) + lw

Area of the patio
= (Area of the pool (with the patio)) - (Area of the pool (w/o the patio))
= (4x² + 2x(l + w) + lw) - lw
Area of the patio = 4x² + 2x(l + w)

Since the area of the patio is equal to the area of the surface of the pool, the area of the patio is equal to the area of the pool without the patio. In terms of the equation,

Area of the patio = Area of the pool (w/o the patio)
4x² + 2x(l + w) = lw
4x² + 2x(l + w) - lw = 0 (1)

Let

a = numerical coefficient of x² = 4
b = numerical coefficient of x = 2(l + w)
c = constant term = -lw

Then using quadratic formula, the roots of the equation 4x² + 2x(l + w) - lw = 0 is given by

$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}
\\ = \frac{-2(l + w) \pm \sqrt{(2(l + w))^2 - 4(4)(-lw)}}{2(4)} 
\\ = \frac{-2(l + w) \pm \sqrt{(4(l + w)^2) + 16lw}}{8} 
\\ = \frac{-2(l + w) \pm \sqrt{(4(l^2 + 2lw + w^2) + 4(4lw)}}{8}
\\ = \frac{-2(l + w) \pm \sqrt{(4(l^2 + 2lw + w^2 + 4lw)}}{8}
\\ = \frac{-2(l + w) \pm \sqrt{(4(l^2 + 6lw + w^2)}}{8}$
$= \frac{-2(l + w) \pm 2\sqrt{l^2 + 6lw + w^2}}{8} \\= \frac{2}{8}(-(l + w) \pm \sqrt{l^2 + 6lw + w^2}) \\x = \frac{1}{4}(-(l + w) \pm \sqrt{l^2 + 6lw + w^2}) \\\boxed{x = \frac{1}{4}\left(-(l + w) + \sqrt{l^2 + 6lw + w^2} \right) \text{ or }}
\\\boxed{x = -\frac{1}{4}\left((l + w) + \sqrt{l^2 + 6lw + w^2} \right)}$

Since $(l + w) + \sqrt{l^2 + 6lw + w^2} \ \textgreater \ 0$ , $-\frac{1}{4}\left((l + w) + \sqrt{l^2 + 6lw + w^2}\right)$ is negative. Since x represents the patio width, x cannot be negative. Hence, the patio width is given by

$\boxed{x = \frac{1}{4}\left(-(l + w) + \sqrt{l^2 + 6lw + w^2} \right)}$

7 0

3 years ago

U = C(1 + rt) solve for t

natita [175]

Answer:

$t = \frac{U -C }{Cr}$

Step-by-step Explanation

$U = C(1+rt) \\ \\ \frac{U}{C} = (1 + rt) \\ \\ \frac{U}{C} - 1 = rt\\ \\ \frac{U -C }{C} = rt\\ \\ \huge \red{ \boxed{ t = \frac{U -C }{Cr} }}$

4 0

3 years ago