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4x^3-3x+9 is divided by 2x-3 |
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Answer» STEP 1: Equation at the end of step 1 STEp 2: 4x3 - 3x + 9 Simplify ———————————— 2x - 3 2.1 Find roots (zeroes) of : F(x) = 4x3 - 3x + 9 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 4 and the Trailing Constant is 9. The factor(s) are: of the Leading Coefficient : 1,2 ,4 of the Trailing Constant : 1 ,3 ,9 Let us test .... P Q P/Q F(P/Q) Divisor -1 1 -1.00 8.00 -1 2 -0.50 10.00 -1 4 -0.25 9.69 -3 1 -3.00 -90.00 -3 2 -1.50 0.00 2x + 3 Note - For TIDINESS, printing of 13 checks which found no root was suppressed 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 4x3 - 3x + 9 can be divided with 2x + 3 Polynomial Long Division : 2.2 Polynomial Long Division Dividing : 4x3 - 3x + 9 ("Dividend") By : 2x + 3 ("Divisor") dividend 4x3 - 3x + 9 - divisor * 2x2 4x3 + 6x2 remainder - 6x2 - 3x + 9 - divisor * -3x1 - 6x2 - 9x remainder 6x + 9 - divisor * 3x0 6x + 9 remainder 0 Quotient : 2x2-3x+3 Remainder: 0 Trying to factor by splitting the MIDDLE term 2.3 Factoring 2x2-3x+3 The first term is, 2x2 its coefficient is 2 . The middle term is, -3x its coefficient is -3 . The last term, "the constant", is +3 Step-1 : Multiply the coefficient of the first term by the constant 2 • 3 = 6 Step-2 : Find two factors of 6 whose sum equals the coefficient of the middle term, which is -3 . -6 + -1 = -7 -3 + -2 = -5 -2 + -3 = -5 -1 + -6 = -7 1 + 6 = 7 2 + 3 = 5 3 + 2 = 5 6 + 1 = 7 Observation : No two such factors can be found !! Conclusion : Trinomial can not be factored 2.4 Polynomial Long Division Dividing : 2x2-3x+3 ("Dividend") By : 2x-3 ("Divisor") dividend 2x2 - 3x + 3 - divisor * x1 2x2 - 3x remainder 3 - divisor * 0x0 remainder 3 Quotient : x Remainder : 3 Final result : (2x2 - 3x + 3) • (2x + 3) ——————————— 2x - 3 |
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