Q. Rewrite the function by completing the square.f(x)=4x2+12x+9f(x)=□(x+□)2+□
Identify coefficients: Identify the quadratic and linear coefficients in the original function.The original function is f(x)=4x2+12x+9. The quadratic coefficient (the coefficient of x2) is 4, and the linear coefficient (the coefficient of x) is 12.
Factor out quadratic coefficient: Factor out the quadratic coefficient from the x2 and x terms.To complete the square, we need to factor out the quadratic coefficient from the x2 and x terms. This gives us:f(x)=4(x2+3x)+9.
Find completion value: Find the value to complete the square.To complete the square for the expression x2+3x, we need to add and subtract (2ab)2, where a is the coefficient of x2 (which is 1 after factoring out the 4) and b is the coefficient of x (which is 3). So we calculate (2⋅13)2=(23)2=49.
Add and subtract value: Add and subtract the value found inside the parentheses.We add and subtract 49 inside the parentheses to complete the square:f(x)=4(x2+3x+49−49)+9.
Write perfect square trinomial: Write the perfect square trinomial and adjust the constant term.The expression x2+3x+49 is a perfect square trinomial, which can be written as (x+23)2. We also need to subtract the 49 that we added inside the parentheses, but since it's multiplied by 4, we subtract 4×49 from the constant term:f(x)=4(x+23)2−4×49+9.
Adjust constant term: Simplify the constant term.Now we simplify the constant term by subtracting 4(49) from 9:f(x)=4(x+23)2−9+9.f(x)=4(x+23)2+0.
Simplify constant term: Write the final form of the function.The function is now written in the form of a completed square:f(x) = 4(x + \frac{3}{2})^2.
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