Every function is a rule which tells you how to associate inputs and outputs. The input, also known as independent variable, is often indicated with the letter 
, while the output, also known as dependent variable, is often indicated with the letter 
.
With this notation, we write 
, read "y is a function of x", in the sense that the value of the variable y depends on the value of the variable x, and f is the function that tells you how y depends on x.
In your example, you have 
, which means "subtract four times the input (4x) from 2"
So, it doesn't matter which input you chose (i.e. the value for x), because you will always have to behave this way:
- Pick an input value, x
- Multiply it by four to get 4x
- Subtract this number from 2: 2-4x
Here are some examples of explicit calculations: if I choose 
and input, the workflow will be
- Pick an input value, 2
- Multiply it by four to get 8
- Subtract this number from 2: 2-8=-6
So, if the input is 2, the output is -6
Similarly, if we choose 
as input, we have:
- Pick an input value, 0
- Multiply it by four to get 0
- Subtract this number from 2: 2-0=2
So, if the input is 0, the output is 2. And so on: for every possible value for x you have the correspondant value for y, with the function f telling you how to associate one with the other.
There are 5 solutions for this system.
x^2 + 4y^2 = 100 ____1
4y - x^2 = -20 ____2
Add both 1 & 2 together. x^2 gets cancelled
4y^2 + 4y = 80 (send 80 to the other side and divide by 4)
Then equation the becomes : y^2 + y -20 =0
Now factorise the equation: (y+5) (y-4) = 0
Solve for y : y = -5 and y = 4
Using the values of y to find the values of x. From equation 1:
x^2 = 100 - 4y^2 x = /100 - 4y^2 (/ means square root) Replace values of y
y = -5, x = /100 - 4(-5)^2 = /100 - 100 = 0
y = 4, x = /100 - 4(4)^2 = / 100 - 64 = /36 = -6 or 6
Thus we have 6 solutions y = -5, 4 and x = -6, 0, 6
In order to find the vector that points from A to B we need to subtract each component of A from the corresponding component of B, according to the formula:
v(a→b)=(b1−a1,b2−a2)
In this case we have :
v(a→b)=(−5−(−8),3−(−1))
<span>v(a→b)=(3,4)
</span>To find the magnitude we use the formula:
||v|= √(v1^2)+(v1^2)
So:
||v|= √(32)+(42)
||v|= √9+16
||v|= <span>√</span>25
||v|= 5
Answer:
a) 2-5 = -3
b) 3(4) + 2(4) = 20
c) (3(5)+2)(5-4) = 17
Step-by-step explanation:
Substitute the variables for their values and then solve from there. Hopefully this helps, I don't know if I answered your question fully.
6 less than 2 and a number.
