McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
6. Solving x^2+bx+c=0
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Exercise 16 Page 49

Start by identifying the values of a, b, and c.

(h+4)(h+11)

Practice makes perfect

To factor the quadratic expression, we will start by identifying the values of a, b, and c. 44+15h+h^2 ⇔ 1h^2+ 15h+ 44 For our expression, we have that a= 1, b= 15, and c= 44. To factor a quadratic expression with leading coefficient a= 1, we need to find two factors of c= 44 whose sum is b= 15. Since 44 is a positive number, we will only consider factors with the same sign — both positive or both negative — so that their product is positive.

Factor Pair Product Sum
1 and 44 ^(1* 44) 44 1+44 45
- 1 and - 44 ^(- 1* (- 44)) 44 ^(- 1+(- 44)) - 45
2 and 22 ^(2* 22) 44 ^(2+22) 24
- 2 and - 22 ^(- 2* (- 22)) 44 ^(- 2+(- 22)) - 24
4 and 11 ^(4* 11) 44 ^(4+11) 15
- 4 and - 11 ^(- 4* (-11)) 44 ^(- 4+(- 11)) - 15

The integers whose product is 44 and whose sum is 15 are 4 and 11. 44+15h+h^2 ⇔ (h+4)(h+11) Let's use a graphing calculator to confirm our answer. To do so, we will graph the related functions in the same coordinate plane. Note that in the calculator we will use the variable x instead of h.

We see that only one graph appears. This means that both graphs coincide. Therefore, the expression has been factored correctly.