Question

Sam's height is 15 centimeters less than 2 times Martha's height. If Sam is 185 centimeters tall, and Martha's height is x, the relationship between the heights can be represented by the equation 2x − 15 = 185. What is Martha's height?

Answer 1

Solve the equation to find out
first, isolate the variable by adding 15 to both sides
2x - 15 = 185
     +15     +15
    -------    ------
 2x-  0   =   200   then simplify
2x= 200
then isolate the variable even more by dividing both sides by 2

2x=200
----   ----
2       2

you will get x=100