Polynomial Synthetic Division

If f(x) = 3x² -9x -20, find the value of f(5) using synthetic substitution.

• 0

• 10

• 15

• -7

What are the coefficients we use?

• 5, 6, 28, 2

• 5, -6, -28, -2

• -5, 6, 28, 2

• -5, -6, -28, -2

What number do we put on the outside?

• -2

• 2

• -5

• 5

What is the first thing we do?

• Bring down the 5 below the line.

• Add all the coefficients

• Divide 5 by -2

• Multiply the 5 and 2

Is this the way to start?

• No, it should be a positive 2 on the outside.

• No, the coefficients are in the wrong order.

• yes

What goes next to the 5 below the line?

• 4

• -16

• 16

• -4

What goes under the -28?

• 32

• -32

• -20

• 20