Multiply a given Integer with 3.5

reference: 

http://www.geeksforgeeks.org/multiply-an-integer-with-3-5/

Problem Definition:

Given a integer x, write a function that multiplies x with 3.5 and returns the integer result. You are not allowed to use %, /, *.

Examples:
Input: 2
Output: 7

Input: 5
Output: 17 (Ignore the digits after decimal point)

Solution:

This could be done by equation (8*x – x)/2 . 

Code:

int multiplyWith3Point5(int x){  return ((x<<3) - x)>>1;}