Take this Exam: National 5 Mathematics: expressions and formulae | Zestly

Question 1

Factorise the expression $9x^2 - 25$.

Accepted Answer

$(3x - 5)(3x + 5)$

Answer

$(9x - 5)(x + 5)$

Answer

$(3x - 5)^2$

Answer

$(9x - 25)(x + 1)$

Question 2

Simplify the algebraic fraction $\frac{x^2 - 16}{x - 4}$, given that $x 
eq 4$.

Accepted Answer

$x + 4$

Answer

$x - 4$

Answer

$x^2 - 4$

Answer

4

Question 3

Given the formula for the volume of a cone $V = \frac{1}{3}\pi r^2 h$, make $h$ the subject.

Accepted Answer

$h = \frac{3V}{\pi r^2}$

Answer

$h = \frac{V}{3\pi r^2}$

Answer

$h = \frac{3V}{(\pi r)^2}$

Answer

$h = \frac{V - 3}{\pi r^2}$

Question 4

Round 0.004528 to two significant figures.

Answer

0.00453

Answer

0.005

Answer

0.0045

Answer

0.0046

Question 5

Given $a = -3$ and $b = 4$, evaluate $a^2 - 2ab$.

Answer

-33

Answer

33

Answer

-15

Answer

15