Answer:
32
Step-by-step explanation:
y= 1.25x+6.75
Make 31.75 y because that is the total cost he paid.
1.25x+6.75=31.75
1.25x=25
x=20
So he had 20 refills.
Answer:
Step-by-step explanation:
If you call "5x-2x^2+1" an "equation," then you must equate 5x-2x^2+1 to 0:
5x-2x^2+1 = 0
This is a quadratic equation. Rearranging the terms in descending order by powers of x, we get:
-2x^2 + 5x + 1 = 0. Here the coefficients are a = -2, b = 5 and c = 1.
Use the quadratic formula to solve for x:
First find the discriminant, b^2 - 4ac: 25 - 4(-2)(1) = 25 + 8 = 33
Because the discriminant is positive, the roots of this quadratic are real and unequal.
-b ± √(discriminant)
Applying the quadratic formula x = --------------------------------
2a
we get:
-5 ± √33 -5 + √33
x = ----------------- = --------------------- and
2(-2) -4
-5 - √33
---------------
-4
Part A
The given expression is:
We expand to get:
Note that 
Part Bi)
The given expression is;
We simplify to get:
Note that:
This is now of the form 
, where 
.
This explains why it is a complex number;
Part bii)
The given expression is :
We simplify to get
Part C
We want to simplify:
We rewrite in terms of 
