If y equals 12 and x equals 3 what is the value of y when x equals 7?

Answer 1

If we are not given the exact relationship between two variables, it is not possible to find the value of one variable corresponding to the value of the other variable. Let us solve it by the two following methods and see the difference.

Method 1

When x=3 then y=12

i.e., y/x=12/3=4

i.e., y=4x

When x=7, then y=4*7=28

Method 2

When x=3 then y=12

i.e., x+y=3+12=15

i.e., y=15-x

When x=7, y=15-7=8