Question

which of the following equations have the solution k=5? show your work

a) k + 5=10 b) 5k=25 c) k - 5=10 d) k/6=5 (k over 6)

Answer 1

$\text{Evaluating each of the options one by one we have:}\\ \text{(a) } k+5 = 10 \quad \text{Subtrating $5$ from both sides we have;}\\ k = 10-5 = 5\\ k = 5\\ \text{(b) } 5k = 25 \quad \text{Dividing both sides by $5$ we have: }\\ k = \frac{25}{5} = 5\\ k = 5\\ \text{(c) } k -5 = 10 \quad \text{Adding $5$ to both sides we have: }\\ k = 10 +5\\ k = 15\\ \text{(d) } \frac{k}{6} = 5 \quad \text{ Multiplying both sides by $6$ we have: }\\ k = 5 \times 6 = 30\\ k = 30\\ \text{From above we observed that only equations (a) } k+5=10 \text{ and (b) } 5k = 25 \text{ are the only equations which have the solution }k = 5$