Verified Answer :
Answer:
Pair of numbers: -3 and -5
Factors : (x-5)(x-3)
Step-by-step explanation:
Given: \(x^2-8x+15\)
We need to factor it using AC method.
For equation: \(ax^2+bx+c\)
For factor this ac and sum b
For our equation: a=1, b=-8 and c=15
Therefore,
Product = ac = (1)(15) = 15
We need to choose two number whose product is 15 and sum -8
First we find all the factor of 15: 1x15 3x5
If we take 3x5
Product: (-3)(-5) = 15
Sum: -3-5 = -8
Pair of numbers: (-3,-5)
Now we will factor it.
\(\Rightarrow x^2-8x+15\)
\(\Rightarrow x^2-5x-3x+15\)
\(\Rightarrow (x^2-5x)+(-3x+15)\)
\(\Rightarrow x(x-5)-3(x-5)\)
\(\Rightarrow (x-5)(x-3)\)
The factors are (x-5) and (x-3)
The pair of numbers that has a product of ac and a sum of b is (x - 5) (x -3.)
What is a quadratic equation?
A quadratic equation is used for the expression of algebraic terms in their second degree. It is used written in the form:
- ax² + bx + c = 0
From the given information:
- x² - 8x + 15 = 0
where;
- a = 1
- b = - 8
- c = 15
To determine the product of ac and the sum of b;
We will look for two values that when we multiply them together, we will have +15 and when we add them together we will have -8.
The two values are -3 and - 5
- The product of -3 and - 15 is ac = +15
- The sum of -3 and -5 is b = -8
Now, the quadratic equation becomes:
x² - 3x - 5x + 15 = 0
x(x -3) -5(x -3) = 0
(x -5) (x - 3) = 0
Learn more about quadratic equations here:
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