NZ Level 6 (NZC) Level 1 (NCEA)
Difference of two squares

## Interactive practice questions

a

Expand $\left(x+5\right)\left(x-5\right)$(x+5)(x5).

b

Hence factorise $x^2-25$x225.

Easy
Approx a minute

Which positive integer must go in the spaces to make the statement true?

What expression must go in the space to make the statement true?

One linear factor of $x^2-49$x249 is $x+7$x+7. What is the other factor?

### Outcomes

#### NA6-5

Form and solve linear equations and inequations, quadratic and simple exponential equations, and simultaneous equations with two unknowns

#### 91027

Apply algebraic procedures in solving problems