Find the difference: -7 -− (-2) = A 9 B -9 C 5 D -5

Solve the right angle trig. round to the nearest tenth.

Tresset [83]

Answer:

x ≈ 58.9

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Geometry

[Right Triangles Only] tan∅ = opposite over adjacent

Step-by-step explanation:

Step 1: Define

We are given a right triangle. We can use trig to find the missing side length.

Step 2: Identify Variables

POV from the angle measure

Angle = 23°

Opposite Leg = 25

Adjacent Leg = x

Step 3: Solve for x

Substitution [tangent]: tan23° = 25/x
Multiply x on both sides: xtan23° = 25
Isolate x: x = 25/tan23°
Evaluate: x = 58.8963
Round: x ≈ 58.9

8 0

3 years ago

WILL MARK BRAINLIEST

Dennis_Churaev [7]

Find the area of the circle

A of circle = πr²

radius = diameter/2 = 48/2 = 24

Area = (3.14)(24)²
Area = 1808.64 in²

Hope this helps :)

6 0

4 years ago

Solve the following equation for x. log(x) + log(x- 3) = log(3x)

Elenna [48]

The answer is x=6
hope this helps!

3 0

2 years ago

A tank contains 60 kg of salt and 1000 L of water. Pure water enters a tank at the rate 6 L/min. The solution is mixed and drain

MissTica

Answer:

(a) 60 kg; (b) 21.6 kg; (c) 0 kg/L

Step-by-step explanation:

(a) Initial amount of salt in tank

The tank initially contains 60 kg of salt.

(b) Amount of salt after 4.5 h

$\text{Let A = mass of salt after t min}\\\text{and }r_{i} = \text{rate of salt coming into tank}\\\text{and }r_{0} =\text{rate of salt going out of tank}$

(i) Set up an expression for the rate of change of salt concentration.

$\dfrac{\text{d}A}{\text{d}t} = r_{i} - r_{o}\\\\\text{The fresh water is entering with no salt, so}\\ r_{i} = 0\\r_{o} = \dfrac{\text{3 L}}{\text{1 min}} \times \dfrac {A\text{ kg}}{\text{1000 L}} =\dfrac{3A}{1000}\text{ kg/min}\\\\\dfrac{\text{d}A}{\text{d}t} = -0.003A \text{ kg/min}$

(ii) Integrate the expression

$\dfrac{\text{d}A}{\text{d}t} = -0.003A\\\\\dfrac{\text{d}A}{A} = -0.003\text{d}t\\\\\int \dfrac{\text{d}A}{A} = -\int 0.003\text{d}t\\\\\ln A = -0.003t + C$

(iii) Find the constant of integration

$\ln A = -0.003t + C\\\text{At t = 0, A = 60 kg/1000 L = 0.060 kg/L} \\\ln (0.060) = -0.003\times0 + C\\C = \ln(0.060)$

(iv) Solve for A as a function of time.

$\text{The integrated rate expression is}\\\ln A = -0.003t + \ln(0.060)\\\text{Solve for } A\\A = 0.060e^{-0.003t}$

(v) Calculate the amount of salt after 4.5 h

a. Convert hours to minutes

$\text{Time} = \text{4.5 h} \times \dfrac{\text{60 min}}{\text{1h}} = \text{270 min}$

b.Calculate the concentration

$A = 0.060e^{-0.003t} = 0.060e^{-0.003\times270} = 0.060e^{-0.81} = 0.060 \times 0.445 = \text{0.0267 kg/L}$

c. Calculate the volume

The tank has been filling at 6 L/min and draining at 3 L/min, so it is filling at a net rate of 3 L/min.

The volume added in 4.5 h is

$\text{Volume added} = \text{270 min} \times \dfrac{\text{3 L}}{\text{1 min}} = \text{810 L}$

Total volume in tank = 1000 L + 810 L = 1810 L

d. Calculate the mass of salt in the tank

$\text{Mass of salt in tank } = \text{1810 L} \times \dfrac{\text{0.0267 kg}}{\text{1 L}} = \textbf{21.6 kg}$

(c) Concentration at infinite time

$\text{As t $\longrightarrow \, -\infty,\, e^{-\infty} \longrightarrow \, 0$, so A $\longrightarrow \, 0$.}$

This makes sense, because the salt is continuously being flushed out by the fresh water coming in.

The graph below shows how the concentration of salt varies with time.

3 0

3 years ago

How do you find the area of a triangle if you only know it's three sides?

DiKsa [7]

You would have to find the height.

To do this, you cut the triangle from the upper vertex to the base to create two new triangles.

Then you use the Law of Cosines. You could use the google calculator for this by searching “law of cosines calculator” and inputting the values, but in case of a test, the formula is a^2 = b^2 + c^2 - 2bc cosA

If you could provide an example of a triangle, I will gladly help you with the steps! Hope this helped!

8 0

3 years ago