Core Connections Algebra 2, 2013
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Core Connections Algebra 2, 2013 View details
2. Section 6.2
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Exercise 119 Page 291

Practice makes perfect
a

The first step is to factor the first two terms so that the x^2-term has a coefficient of 1. In this case, that means factoring out 4.

f(x)=4x^2-12x+6 = 4(x^2-3x)+6 The coefficient in front x is -3. Half of that is -1.5 so the perfect square is (x-1.5)^2. Since we factored out 4 we should now, according to Sarah, subtract 4(-1.5)^2 to ensure that the equation is equivalent, giving us the following expression. f(x)=4(x-1.5)^2-4(-1.5)^2+6 Let's simplify.

f(x)=4(x-1.5)^2-4(-1.5)^2+6
â–¼
Simplify right-hand side
f(x)=4(x-1.5)^2-4*2.25+6
f(x)=4(x-1.5)^2-9+6
f(x)=4(x-1.5)^2-3

Now we have the function in graphing form, also known as vertex form. f(x)=4(x-1.5)^2-3 This means that the axis of symmetry is x=1.5 and the vertex is (1.5,- 3).

b

We do the same thing as in the previous exercise, and start by factoring the first two terms.

g(x)=2x^2+14x+4= 2(x^2+7x)+4 The x-coefficient is 7, and half of that is 3.5. This means that the perfect square is (x+3.5)^2, but since we factored out 2 we need to subtract 2*3.5^2. g(x)=2(x^2+7x)+4=2(x+3.5)^2-2* 3.5^2+4 Let's rewrite.

g(x)=2(x+3.5)^2-2* 3.5^2+4
â–¼
Simplify right-hand side
g(x)=2(x+3.5)^2-2*12.25+4
g(x)=2(x+3.5)^2-24.5+4
g(x)=2(x+3.5)^2-20.5

a+b=a-(- b)

g(x)=2(x-(-3.5))^2+(- 20.5)

The graphing form is as follows. g(x)=2(x-(-3.5))^2+(- 20.5) Thus, the axis of symmetry is x=-3.5, and the vertex is (-3.5,-20.5).