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Question

Question: Solve the given quadratic equation: \[44{x^2} - x - 3 = 0\]....

Solve the given quadratic equation:
44x2x3=044{x^2} - x - 3 = 0.

Explanation

Solution

Here we have a quadratic equation, we can solve this using factorization method or by quadratic formula or by graphing method or by completing square method. We solve this using the factorization method. If we fail to split the middle term we use quadratic formula, that is x=b±b24ac2ax = \dfrac{{ - b \pm \sqrt {{b^2} - 4ac} }}{{2a}}.

Complete step-by-step solution:
Given, 44x2x3=044{x^2} - x - 3 = 0.
Now consider the equation 44x2x3=044{x^2} - x - 3 = 0. The degree of this equation is two hence we will have two factors.
On comparing the given equation with the standard quadratic equation ax2+bx+c=0a{x^2} + bx + c = 0. We have a=44a = 44, b=1b = - 1 and c=3c = - 3.
For factorization, the standard equation is rewritten as ax2+b1x+b2x+c=0a{x^2} + {b_1}x + {b_2}x + c = 0 such thatb1×b2=ac{b_1} \times {b_2} = ac andb1+b2=b{b_1} + {b_2} = b.
Here we can say that b1=12{b_1} = - 12 and b2=11{b_2} = 11. Because b1×b2=132{b_1} \times {b_2} = - 132 (a×c)(a \times c) and b1+b2=1(b){b_1} + {b_2} = - 1(b).
Now we write 44x2x3=044{x^2} - x - 3 = 0 as,
44x212x11x3=0\Rightarrow 44{x^2} - 12x - 11x - 3 = 0
Taking ‘4x’ common in the first two terms and taking 1-1 common in the remaining two terms we have,
4x(11x3)1(11x3)=0\Rightarrow 4x(11x - 3) - 1(11x - 3) = 0
Again taking (11x3)(11x - 3) common we have,
(11x3)(4x1)=0(11x - 3)(4x - 1) = 0.
By zero product principle we have,
(11x3)=0\Rightarrow (11x - 3) = 0 and (4x1)=0(4x - 1) = 0
11x=3\Rightarrow 11x = 3 and 4x=14x = 1
x=113\Rightarrow x = \dfrac{{11}}{3} and x=14x = \dfrac{1}{4}.
This is the required solution.

Note: The highest exponent of the polynomial in a polynomial equation is called its degree. A polynomial equation has exactly as many roots as its degree. Suppose if we have a cubic equation, then we need to reduce it to a quadratic equation using synthetic division and reduce it to a quadratic equation. We can solve the quadratic equation easily.