Factor by Guess and Check

What is the first step to solving our quadratic ?

• Subtract 10 to both sides

• Divide by 7

• Factor

Tags

CCSS.HSA-REI.B.4B

What goes in this box ?

• 7x

• x²

• 10

What goes in this box ?

• 7

• x²

• 10

Tags

CCSS.HSA-REI.B.4B

20x³-25x²+4x-5

• (5x²-5)(4x+1)

• 5(x²-1)(4x+5)

• (5x²+1)(4x-5)

• (5x²+1)(4x-1)

7r³ - 8r² + 42r - 48

• (r²+6)(7r+8)

• (r²+6)(7r-8)

• (r²+6)(r²+8)

• (r²+6)(7r+6)

Factorise: x²+4x-5

To find what goes in these two boxes, we need to find the factors of ____

• 1

• 7

• 10

Tags

CCSS.HSA-REI.B.4B

Since 2 and 5 are factors of 10 and 2+5=7, then x²+7x+10 = (x + __) (x+ __)

• 1 and 10

• 2 and 5

• 7 and 10

Tags

CCSS.HSA-REI.B.4B

Since (x + 5) (x+ 2) = 0, then by the zero product property

• (x+5)=0 and (x+2)=0

• (x+5)=(x+2)

• (x+5)= - (x+2)

Tags

CCSS.HSA-REI.B.4B