You just substitute the value of x in the given equation:
f(x) = 2x^2 - 5
f(-4) = 2 (-4)^2 -5 = 27
f(x) : a name given to the equation
f(-4): refer to the equation when the value of the independent variable x has the value between the brackets.
Answer:
4 
Step-by-step explanation:
The additive inverse is the value that must be added to the number to give zero.
- 4
+ 4
= 0
↑ additive inverse
Based on the calculations that 300 is 40%, 375 is considered 50% or halfway.. in this case, we must multiply 375 by 2 and we will discover how many students were surveyed:
375 x 2 = 750
1/4x - 2 = 3/8
First, to start solving this, we can rearrange our fraction. Let's take 1/4x and change it to x/4. Why? Well, a variable can also be considered as the number 1.

Second, now we can continue solving for our variable (x). Let's add 2 to each side.

Third, let's simplify 3/8 + 2. (3/8 + 2 = 2.375 =19/8)

Fourth, continue trying to get the variable by itself. Multiply each side by 4.

Fifth, let's simplify 19/8 × 4. This is simple. Leave the denominator be and just do 19 × 4, which equals 76.

Sixth, our final step is to simplify our fraction. To do so, we will need to list the factors of the numerator and denominator and find the greatest common factor (GCF).
Factors of 76: 1, 2, 4, 19, 38, 76
Factors of 8: 1, 2, 4, 8
Since 4 is our first common factor, it is considered our GCF.
Seventh, now let's divide. Divide both the numerator and denominator by the GCF (4) to create our new simplified fraction.

Answer in fraction form:

Answer in decimal form:
Answer:
Step-by-step explanation:
The formula for determining the the area of a sector is expressed as
Area of Sector = θ/360 × πr²
Where
θ represents the central angle.
π is a constant whose value is 3.14
r represents the radius of the circle.
From the information given,
The central angle is π/7 radian. Converting to degrees, it becomes
π/7 × 180/π = 180/7 = 25.714 degrees.
Area of sector = 77 square meters
Therefore
77 = 25.714/360 × 3.14 × r²
77 = 0.2243r²
r² = 77/0.2243 = 343.29
r = √343.29 = 18.53 meters