A rational number is a number that can be written as a ratio. That means it can be written as a fraction, in which both the numerator (the number on top) and the denominator (the number on the bottom) are whole numbers. The number 8 is a rational number because it can be written as the fraction 8/1.
<span>y = 3x² + 18x
factor out the leading coefficient
y = 3(x²+6x)
Complete the square
coefficient of the x term: 6
divide it in half: 3
square it: 3²
use 3² to complete the square:
y = 3(x²+6x + 3²) - 3·3²
= 3(x+3)² - 3·3²
= 3(x+3)² - 27
vertex (-3, -27)</span>
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F(3)={2(3)-9}
F(3)={6-9}
F(3)={-3}
