Question 15 Marks
If m is a whole number less than $5,$ complete the table and by inspection of the table, find the solution of the equation $2m - 5 = -1:$
| $m$ | |||||
| $2m - 5$ |
Answer
View full question & answer→Since, m is a whole number which is less than $5,$ then solution of the equation is given by putting the value ofm $= 0, 1, 2, 3, 4, ...$
Now, put $m = 0,$ then
$= 2m - 5 = 2 \times 0 - 5$
$= -5$
Put $m = 1,$ then
$= 2m - 5 = 2 \times 1 - 5$
$= -3$
Put $m = 2,$ then
$= 2m - 5 = 2 \times 2 - 5 = 4 - 5$
$= -1$
Put $m = 3,$ then
$= 2m - 5 = 2 \times 3 - 5 = 6 - 5$
$= 1$
Put $m = 4,$ then
$= 2m - 5 = 2 \times 4 - 5$
$= 3$
Hence, table is:
and given equation is $2m - 5 = -1$
$\Rightarrow 2m = -1 + 5 [$transposing $-5$ to $RHS]$
$\Rightarrow 2m = 4$
$\Rightarrow\frac{2\text{m}}{2}=\frac{4}{2} [$dividing both sides by $2]$
$\Rightarrow m = 2$
Now, put $m = 0,$ then
$= 2m - 5 = 2 \times 0 - 5$
$= -5$
Put $m = 1,$ then
$= 2m - 5 = 2 \times 1 - 5$
$= -3$
Put $m = 2,$ then
$= 2m - 5 = 2 \times 2 - 5 = 4 - 5$
$= -1$
Put $m = 3,$ then
$= 2m - 5 = 2 \times 3 - 5 = 6 - 5$
$= 1$
Put $m = 4,$ then
$= 2m - 5 = 2 \times 4 - 5$
$= 3$
Hence, table is:
| $m$ | $0$ | $1$ | $2$ | $3$ | $4$ |
| $2m - 5$ | $-5$ | $-3$ | $-1$ | $1$ | $3$ |
$\Rightarrow 2m = -1 + 5 [$transposing $-5$ to $RHS]$
$\Rightarrow 2m = 4$
$\Rightarrow\frac{2\text{m}}{2}=\frac{4}{2} [$dividing both sides by $2]$
$\Rightarrow m = 2$