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2 years ago

Evaluate 5x3 - 21 + 7 when x = -2.

Mathematics

2 answers:

Sliva [168]2 years ago

8 0

Answer:

Step-by-step explanation:

5x³ - 21 + 7

x = 2

then:

5x³ - 14

5*2³ -14

5*8 - 14

40 - 14

OverLord2011 [107]2 years ago

8 0

Answer:

The simplified answer to the given equation is -54.

Step-by-step explanation:

For this problem, we are given the value of x.

x = -2

So, let's plug in this value into our expression soit can be easier to solve.

5(-2)³ - 21 + 7

First, simplify the exponents.

5(-8) - 21 + 7

Now, multiply 5 by -8.

-40 - 21 + 7

Subtract -40 from 21.

-61 + 7

Add 7 to -61.

-54

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ale4655 [162]

1 hour = 50 km
3 hours = 50 x 3 = 150 km

Answer: The car would go for 150 km in 3 hours.

8 0

3 years ago

A movie complex is showing the same movie and three theaters in theater and a 60 of the 80 seats are taken and theater B 42 seat

Anna [14]

Answer:

Theatre C.

Step-by-step explanation:

Theatre A:

60 of the 80 seats are taken.

% seats taken = seats taken/total seats * 100

= 60/80 * 100

= 75%

Theatre B:

Total seats = number of seats taken + number of empty seats

= 42 + 18

= 60

% seats taken = seats taken/total seats * 100

= 42/60 * 100

= 70%

Theatre C:

Total seats = number of seats taken + number of empty seats

90 = X + 18

X = 72

% seats taken = seats taken/total seats * 100

= 72/90 * 100

= 80%

Theatre C with 80% of seats taken.

4 0

3 years ago

Read 2 more answers

Find the derivative.

krek1111 [17]

Answer:

$\displaystyle f'(x) = \bigg( \frac{1}{2\sqrt{x}} - \sqrt{x} \bigg)e^\big{-x}$

General Formulas and Concepts:

Algebra I

Terms/Coefficients

Expanding/Factoring

Calculus

Differentiation

Derivatives
Derivative Notation

Basic Power Rule:

f(x) = cxⁿ
f’(x) = c·nxⁿ⁻¹

Derivative Rule [Quotient Rule]: $\displaystyle \frac{d}{dx} [\frac{f(x)}{g(x)} ]=\frac{g(x)f'(x)-g'(x)f(x)}{g^2(x)}$

Step-by-step explanation:

Step 1: Define

Identify

$\displaystyle f(x) = \frac{\sqrt{x}}{e^x}$

Step 2: Differentiate

Derivative Rule [Quotient Rule]: $\displaystyle f'(x) = \frac{(\sqrt{x})'e^x - \sqrt{x}(e^x)'}{(e^x)^2}$
Basic Power Rule: $\displaystyle f'(x) = \frac{\frac{e^x}{2\sqrt{x}} - \sqrt{x}(e^x)'}{(e^x)^2}$
Exponential Differentiation: $\displaystyle f'(x) = \frac{\frac{e^x}{2\sqrt{x}} - \sqrt{x}e^x}{(e^x)^2}$
Simplify: $\displaystyle f'(x) = \frac{\frac{e^x}{2\sqrt{x}} - \sqrt{x}e^x}{e^{2x}}$
Rewrite: $\displaystyle f'(x) = \bigg( \frac{e^x}{2\sqrt{x}} - \sqrt{x}e^x \bigg) e^{-2x}$
Factor: $\displaystyle f'(x) = \bigg( \frac{1}{2\sqrt{x}} - \sqrt{x} \bigg)e^\big{-x}$