8n^2-4n-180
(factories)
Answers
Answer:
Step by step solution :
STEP
1
:
Equation at the end of step 1
(23n2 - 4n) - 180 = 0
STEP
2
:
STEP
3
:
Pulling out like terms
3.1 Pull out like factors :
8n2 - 4n - 180 = 4 • (2n2 - n - 45)
Trying to factor by splitting the middle term
3.2 Factoring 2n2 - n - 45
The first term is, 2n2 its coefficient is 2 .
The middle term is, -n its coefficient is -1 .
The last term, "the constant", is -45
Step-1 : Multiply the coefficient of the first term by the constant 2 • -45 = -90
Step-2 : Find two factors of -90 whose sum equals the coefficient of the middle term, which is -1 .
-90 + 1 = -89
-45 + 2 = -43
-30 + 3 = -27
-18 + 5 = -13
-15 + 6 = -9
-10 + 9 = -1 That's it
Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above, -10 and 9
2n2 - 10n + 9n - 45
Step-4 : Add up the first 2 terms, pulling out like factors :
2n • (n-5)
Add up the last 2 terms, pulling out common factors :
9 • (n-5)
Step-5 : Add up the four terms of step 4 :
(2n+9) • (n-5)
Which is the desired factorization
Equation at the end of step
3
:
4 • (n - 5) • (2n + 9) = 0
STEP
4
:
Theory - Roots of a product
4.1 A product of several terms equals zero.
When a product of two or more terms equals zero, then at least one of the terms must be zero.
We shall now solve each term = 0 separately
In other words, we are going to solve as many equations as there are terms in the product
Any solution of term = 0 solves product = 0 as well.
Equations which are never true:
4.2 Solve : 4 = 0
This equation has no solution.
A a non-zero constant never equals zero.
Answer:
Step-by-step explanation: