Question

Factor each completely.1) x7x 18

Answer 1

Hello,

x²-7x-18=x²+2x-9x-18
=x(x+2)-9(x+2)
=(x+2)(x-9)

Answer 2

Use the cross-method.

1. Draw a cross.

2. Put x^2 to the first column.

( You can put any x^2 values for other similar factorisation question. eg. 5x^2 )

3. Put numbers on the 2nd column.

4. For the last column, it must be a number with an x.

5. Make sure that all the numbers and algebra that you multiplied gives the product with the ones at the bottom row.

6. Cross multiply.

7. Take 1st row and bracket them and do the same for 2nd row.

Answer:

x^2 - 7x - 18

= ( x+2 )( x - 9 )