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Question

Question: How do you factor \(4{{m}^{4}}-37{{m}^{2}}+9\)?...

How do you factor 4m437m2+94{{m}^{4}}-37{{m}^{2}}+9?

Explanation

Solution

For answering this question we will use factorization. Factorization is the process of deriving factors of a number which divides the given number evenly. For this question we will split the constant term and we will use the sum product pattern of splitting and then we will simplify the equation using the x2a2=(x+a)(xa)\Rightarrow {{x}^{2}}-{{a}^{2}}=\left( x+a \right)\left( x-a \right) formula and simplify until we get the solution.

Complete step-by-step solution:
Now considering from the question we have an expression 4m437m2+94{{m}^{4}}-37{{m}^{2}}+9 for which we need to derive the factors.
We can factor the 4m437m2+94{{m}^{4}}-37{{m}^{2}}+9 by below method:
Given equation is in the form of ax4+bx2+c=0a{{x}^{4}}+b{{x}^{2}}+c=0.
First, we have to divide the coefficient of term in the equation which is 37-37 into the sum of the two numbers and must make sure that the product of the two numbers must be equal to the product of the coefficient of m4{{m}^{4}} and constant that is product of 44and 99.
Now, the product can be split into the product of the two numbers as 36×1-36\times -1.
here we have to take the splitting of37-37 as the sum of 36-36 and 1-1 which is equal to the coefficient of m2{{m}^{2}}.
Their sum is also equal to 1010which is equal to the coefficient of x2{{x}^{2}}.
So, the given question can be factored as follows.
4m437m2+9\Rightarrow 4{{m}^{4}}-37{{m}^{2}}+9
4m436m2m2+9\Rightarrow 4{{m}^{4}}-36{{m}^{2}}-{{m}^{2}}+9
Here, we will take 4m24{{m}^{2}}common in the first two terms and proceed further.
4m2(m29)(m29)\Rightarrow 4{{m}^{2}}\left( {{m}^{2}}-9 \right)-\left( {{m}^{2}}-9 \right)
(4m21)(m29)\Rightarrow \left( 4{{m}^{2}}-1 \right)\left( {{m}^{2}}-9 \right)
Here, we will use the formula x2a2=(x+a)(xa)\Rightarrow {{x}^{2}}-{{a}^{2}}=\left( x+a \right)\left( x-a \right) and proceed the further calculation.
(2m1)(2m+1)(m3)(m+3)\Rightarrow \left( 2m-1 \right)\left( 2m+1 \right)\left( m-3 \right)\left( m+3 \right)
Therefore, the factors will be(2m1)(2m+1)(m3)(m+3)\Rightarrow \left( 2m-1 \right)\left( 2m+1 \right)\left( m-3 \right)\left( m+3 \right).

Note: During answering questions of this type, we should be sure with our calculations. Let us assume that m2=x{{m}^{2}}=x so the equation will become as 4x237x+9\Rightarrow 4{{x}^{2}}-37x+9 answering this question we can also use the formulae for obtaining the roots of the quadratic equation ax2+bx+c=0a{{x}^{2}}+bx+c=0 given as b±b24ac2a\dfrac{-b\pm \sqrt{{{b}^{2}}-4ac}}{2a} then if the two solutions are p,qp,q then the factors will be (xp)(xq)\left( x-p \right)\left( x-q \right) . For 4x237x+9\Rightarrow 4{{x}^{2}}-37x+9 the roots are 37±13694(9×4)2×4=37±358=728,28=9,14\dfrac{37\pm \sqrt{1369-4\left( 9\times 4 \right)}}{2\times 4}=\dfrac{37\pm 35}{8}=\dfrac{72}{8},\dfrac{2}{8}=9,\dfrac{1}{4} then the factors will be x14x-\dfrac{1}{4} and x9x-9.
Later, we will replace ours m2=x{{m}^{2}}=x. So, the solution will be (m214)(m29)\Rightarrow \left( {{m}^{2}}-\dfrac{1}{4} \right)\left( {{m}^{2}}-9 \right) and for further simplification we use x2a2=(x+a)(xa)\Rightarrow {{x}^{2}}-{{a}^{2}}=\left( x+a \right)\left( x-a \right) formula and get our final solution as follows (2m1)(2m+1)(m3)(m+3)\Rightarrow \left( 2m-1 \right)\left( 2m+1 \right)\left( m-3 \right)\left( m+3 \right). Therefore, the factors will be (2m1)(2m+1)(m3)(m+3)\Rightarrow \left( 2m-1 \right)\left( 2m+1 \right)\left( m-3 \right)\left( m+3 \right).