Day 4 - Easy Trinomials

Day 4 - Easy Trinomials

Warmup - Use FOIL or distributive property to multiply

 $\left(x+2\right)\left(x+3\right)$  

•  $x^2+3x+2x+6$  

•  $x^2+5x+6$  

Factoring Trinomials

• We are essentially going in reverse

•  $x^2+5x+6\ \rightarrow\ \left(x+2\right)\left(x+3\right)$  

• What pattern do you notice? (Where do we get the 5 and 6?)

• Standard form:  $ax^2+bx+c$  This form will help us understand later when I call terms by 'a, b, and c'.

Factoring

 $x^2+7x+12$  

• In the previous problem, we found two numbers that multiplied to our 'c' (6), and added to our 'b' (5)

• In this case, what are two numbers that multiply to our 'c' (12), and add to 'b' (7)?

• 4 & 3, right?

• So our two factors would be  $\left(x+4\right)\left(x+3\right)$  (FOIL this back out to check your answer!)

Multiple Choice

Factor:
 b² + 8b + 7

• (b + 4)(b + 3)
• (b + 6)(b + 1)
• (b + 7)(b +1)
• prime

Multiple Choice

Factor
k²+7x+10

• (k+2)(k+5)
• (k-2)(k-5)
• (k+10)(k+4)
• (k+2)(k-5)

Factor

 $x^2-5x-14$  

• Same method applies - look for factors that multiply to -14, and add to -5. Try this on your own first!

• -7, 2 ? ( $-7\cdot2=-14;\ -7+2=-5$  )

•  $\left(x-7\right)\left(x+2\right)$