Questions: g(x)=-4x^2-12x+9

g(x)=-4x^2-12x+9
Transcript text: 39. $g(x)=-4 x^{2}-12 x+9$
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Solution

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Solution Steps

To find the roots of the quadratic function g(x)=4x212x+9 g(x) = -4x^2 - 12x + 9 , we can use the quadratic formula x=b±b24ac2a x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} , where a=4 a = -4 , b=12 b = -12 , and c=9 c = 9 .

Step 1: Identify the Quadratic Function

We are given the quadratic function g(x)=4x212x+9 g(x) = -4x^2 - 12x + 9 . To find the roots of this function, we will use the quadratic formula.

Step 2: Calculate the Discriminant

The discriminant D D is calculated using the formula: D=b24ac D = b^2 - 4ac Substituting the values a=4 a = -4 , b=12 b = -12 , and c=9 c = 9 : D=(12)24(4)(9)=144+144=288 D = (-12)^2 - 4(-4)(9) = 144 + 144 = 288

Step 3: Find the Roots

Using the quadratic formula: x=b±D2a x = \frac{-b \pm \sqrt{D}}{2a} we substitute b=12 b = -12 , D=288 D = 288 , and a=4 a = -4 : x=12±2888 x = \frac{12 \pm \sqrt{288}}{-8} Calculating the square root: 288=16.9706(rounded to four significant digits) \sqrt{288} = 16.9706 \quad (\text{rounded to four significant digits}) Thus, the roots are: x1=12+16.970683.6213 x_1 = \frac{12 + 16.9706}{-8} \approx -3.6213 x2=1216.970680.6213 x_2 = \frac{12 - 16.9706}{-8} \approx 0.6213

Final Answer

The roots of the quadratic function g(x) g(x) are approximately: x13.6213 \boxed{x_1 \approx -3.6213} x20.6213 \boxed{x_2 \approx 0.6213}

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