Step-by-step explanation:
1 result(s) found
x
2
−x−3
Step by Step Solution:
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STEP
1
:
Equation at the end of step 1
STEP
2
:
x3 + 3x2 - 7x - 12
Simplify ——————————————————
x + 4
Checking for a perfect cube :
2.1 x3 + 3x2 - 7x - 12 is not a perfect cube
Trying to factor by pulling out :
2.2 Factoring: x3 + 3x2 - 7x - 12
Thoughtfully split the expression at hand into groups, each group having two terms :
Group 1: -7x - 12
Group 2: x3 + 3x2
Pull out from each group separately :
Group 1: (7x + 12) • (-1)
Group 2: (x + 3) • (x2)
Bad news !! Factoring by pulling out fails :
The groups have no common factor and can not be added up to form a multiplication.
Polynomial Roots Calculator :
2.3 Find roots (zeroes) of : F(x) = x3 + 3x2 - 7x - 12
Polynomial Roots Calculator is a set of methods aimed at finding values of x for which F(x)=0
Rational Roots Test is one of the above mentioned tools. It would only find Rational Roots that is numbers x which can be expressed as the quotient of two integers
The Rational Root Theorem states that if a polynomial zeroes for a rational number P/Q then P is a factor of the Trailing Constant and Q is a factor of the Leading Coefficient
In this case, the Leading Coefficient is 1 and the Trailing Constant is -12.
The factor(s) are:
of the Leading Coefficient : 1
of the Trailing Constant : 1 ,2 ,3 ,4 ,6 ,12
Let us test
P Q P/Q F(P/Q) Divisor
-1 1 -1.00 -3.00
-2 1 -2.00 6.00
-3 1 -3.00 9.00
-4 1 -4.00 0.00 x + 4
-6 1 -6.00 -78.00
-12 1 -12.00 -1224.00
1 1 1.00 -15.00
2 1 2.00 -6.00
3 1 3.00 21.00
4 1 4.00 72.00
6 1 6.00 270.00
12 1 12.00 2064.00
The Factor Theorem states that if P/Q is root of a polynomial then this polynomial can be divided by q*x-p Note that q and p originate from P/Q reduced to its lowest terms
In our case this means that
x3 + 3x2 - 7x - 12
can be divided with x + 4
Polynomial Long Division :
2.4 Polynomial Long Division
Dividing : x3 + 3x2 - 7x - 12
("Dividend")
By : x + 4 ("Divisor")
dividend x3 + 3x2 - 7x - 12
- divisor * x2 x3 + 4x2
remainder - x2 - 7x - 12
- divisor * -x1 - x2 - 4x
remainder - 3x - 12
- divisor * -3x0 - 3x - 12
remainder 0
Quotient : x2-x-3 Remainder: 0
Trying to factor by splitting the middle term
2.5 Factoring x2-x-3
The first term is, x2 its coefficient is 1 .
The middle term is, -x its coefficient is -1 .
The last term, "the constant", is -3
Step-1 : Multiply the coefficient of the first term by the constant 1 • -3 = -3
Step-2 : Find two factors of -3 whose sum equals the coefficient of the middle term, which is -1 .
-3 + 1 = -2
-1 + 3 = 2
Observation : No two such factors can be found !!
Conclusion : Trinomial can not be factored
Canceling Out :
2.6 Cancel out (x+4) which appears on both sides of the fraction line.
Final result :
x2 - x - 3
Terms and topics
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Polynomial root calculator
Polynomial long division
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