Quadratic Expressions and Equations

Expanding quadratic expressions using the grid method (C)

Expanding using the Grid Method

(x + 4)(x + 3)

x² + 4x + 3x + 12

x² + 7x + 12

Exam

ple

s

x + 4

x

+ 3

x² + 4x

+ 3x

+ 12

A really common

mistake here is adding 4 and 3

instead of multiplying

them.

Multiply each term (just like normal grid multiplication)

Then add together the terms inside the grid.

Finally, simplify your answer by collecting like terms.

Then add together the terms inside the grid.

Finally, simplify your answer by collecting like terms.

Expanding using the Grid Method

(x + 2)(x - 5)

x² + 2x - 5x - 10

x² - 3x - 10

Exam

ple

s

x + 2

x

- 5

x² + 2x

- 5x - 10

+ × - = -

Multiply each term (just like normal grid multiplication)

Add together.

Simplify.

Expanding using the Grid Method

(4x + 3)(2x + 4)

8x² + 6x + 16x + 12

8x² +24x + 12

Exam

ple

s

4x + 3

2x

+ 4

8x² + 6x

+ 16x

+ 12

4x × 2x = 8x²(multiply)

Multiply each term.

Add together.

Simplify.

Expanding using the Grid Method

(6x + 2)(4x - 3)

24x² + 8x - 18x - 6

24x² - 10x - 6

Exam

ple

s

6x + 2

4x

- 3

24x² + 8x

- 18x - 6

Multiply each term.