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 6 Page 49

Rewrite - 3n as the sum of two terms whose coefficients have a product of 2.

1 and 2

Practice makes perfect

To solve the given equation, we will start by factoring the left-hand side.

Factoring

Since the leading coefficient is 1, we need to rewrite - 3n as the sum of two terms whose coefficients have a product of 2. - 1 +(- 2)&= - 3 - 1(- 2)&= 2 Since - 1 and - 2 are two numbers whose sum is - 3 and whose product is 2, we will rewrite - 3n as - 1n+(- 2)n. Note that this expression can be simplified. - 1n+(- 2)n ⇔ - n-2n Therefore, we will start by rewriting - 3n as - n-2n.

n^2-3n+2=0
n^2-n-2n+2=0
â–¼
Factor out n & -2
n(n-1)-2n+2=0
n(n-1)-2(n-1)=0
(n-1)(n-2)=0

Solving

To solve this equation, we will apply the Zero Product Property.

(n-1)(n-2)=0
lcn-1=0 & (I) n-2=0 & (II)
ln=1 n-2=0
ln=1 n=2

Checking the Answer

We can substitute our solutions back into the given equation and simplify to check if our answers are correct. We will start with n=1.

n^2-3n+2=0
1^2-3( 1)+2? =0
â–¼
Simplify
1-3(1)+2? =0
1-3+2? =0
0=0 ✓

Substituting and simplifying created a true statement, so we know that n=1 is a solution to the equation. Let's move on to n=2.

n^2-3n+2=0
2^2-3( 2)+2? =0
â–¼
Simplify
4-3(2)+2? =0
4-6+2? =0
0=0 ✓

Again, we obtained a true statement. Therefore, n=2 is indeed a solution to the equation.