Practise online Get the app

Paper 1 · November 2019 · Logarithms and Exponentials

Solve the equation $3^{x-1} + 3^{x-2} = 12$ .

A

x = 3

B

x = 4

C

x = 27

D

x = 2

Explanation

\tfrac{3^x}{3}+\tfrac{3^x}{9}=\tfrac{4(3^x)}{9}=12

, so

3^x=27=3^3

and

x=3

.

Derived from ZIMSEC Mathematics Paper 1, November 2019, Q1

View this paper's sittings and topics→

More questions from this paper

Solve the inequality $|3^{-3x} - 54| < 27$ .
In triangle $ABC$ the sides $BC$ , $CA$ and $AB$ are $a$ , $b$ and $c$ respectively, and $\cot C = \dfrac{a}{c}\operatorname{cosec} B - \cot B$ . Given $a = 14.7$ cm, $c = 17.3$ cm and $B = 64.2°$ , find angle $C$ correct to the nearest $0.1°$ .
In triangle $ABC$ , $a = 14.7$ cm, $c = 17.3$ cm, $B = 64.2°$ and $C = 65.3°$ . Find angle $A$ correct to the nearest $0.1°$ .
The diagram shows the graph of $y = f(x)$ , passing through $A(-1, 0)$ , $B(0, 1)$ and $C(1, 0)$ . On the graph of $y = f(-x) + 3$ , the image of $B$ is
A teacher earns $\$x$ in his first year and his salary increases each year by 10% of his first year's salary. His total salary after $n$ years is

Get the full paper, not just one question

Danho has every sitting for this paper, with your progress tracked question by question, offline.

Get it on Google Play Download on the App Store