New Zealand
Level 7 - NCEA Level 2

# Solving by completing the square II

## Interactive practice questions

How can we find the number to add to $x^2-5x$x25x to make a perfect square trinomial?

Halve the coefficient of $x$x.

A

Square the coefficient of $x^2$x2.

B

Halve the coefficient of $x$x and then square it.

C

Square the coefficient of $x$x.

D

Halve the coefficient of $x$x.

A

Square the coefficient of $x^2$x2.

B

Halve the coefficient of $x$x and then square it.

C

Square the coefficient of $x$x.

D
Easy
Less than a minute

Find the value(s) of $k$k that will make $x^2+kx+16$x2+kx+16 a perfect square trinomial.

If there is more than one value, write all of them on the same line, separated by commas.

Solve the following quadratic equation noting that the left hand side is a perfect square. Leave the answer in surd form.

$\left(x+2\right)^2=20$(x+2)2=20

Solve for $x$x:

$\left(x-10\right)^2=26$(x10)2=26

### Outcomes

#### M7-7

Form and use linear, quadratic, and simple trigonometric equations

#### 91261

Apply algebraic methods in solving problems