McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
9. Perfect Squares
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Exercise 7 Page 68

Start by identifying the values of a, b, and c. Be sure that all of the terms of are on the same side and in the correct order for the standard form of a quadratic function.

±3

Practice makes perfect
To solve the given equation by factoring, we will start by identifying the values of a, b, and c. 4x^2=36 ⇔ 4x^2+( - 36)=0 Notice that this equation follows a special pattern. It can be factored as a difference of squares.
4x^2-36
4(x^2-9)
4(x+3)(x-3)
Now we are ready to use the Zero Product Property.
4(x+3)(x-3)=0
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Solve using the Zero Product Property
lcx+3=0 & (I) x-3=0 & (II)
lx=- 3 x-3=0
lx=- 3 x=3
We found that the solutions to the given equation are x=- 3 and x=3. To check our answer, we will graph the related functions y=4x^2-36 and y=4(x+3)(x-3) in the same coordinate plane using a graphing calculator.

We see that only one graph appears. This means that both graphs coincide. We can see that the x-intercepts are - 3 and 3. Therefore, are solutions are correct. âś“