Question

20% of 840-x% of 500 =100

Answer 1

20% of 840-x% of 500=100

20*840/100-x*500/100=100

168-x*500/100=100

-x*500/100=100-168

x*500/100=68

x*500=6800

x=6800/500

x=68/5

x=13.6

Answer 2

Hey mate!!

Here's your answer!!

$\frac{20}{100} \times 840- \frac{x}{100} \times 500 = 100 \\ \\ = > 168 - 5x = 100 \\ = > ( - 5x) = 100 - 168 \\ = > ( - 5x) = ( - 68) \\ = > 5x = 68 \\ \\ = > x = \frac{68}{5} \\ \\ = > x = 13.6$


Hope it helps!!