
1st step you subtract 7 from both sides and the 7 get cancelled so you will get

2nd step you divide by 10 from both sides so you will get

3rd step is that you final answer is
'of' can be tranlated as multiply
percent means parts out of 100 so
6.1%=6.1/100=0.61/10=0.061
so multiply 0.061 with 60=3.66
the number is 3.66
If you reflect over the line y = -x, the x-coordinate and y-coordinate change places and are negated (the signs are changed).
If you are using a calculator, simply enter 78÷260×100 which will give you 30 as the answer.