For linear regression line, you need y^ = a + bx, where b = r(sy/sx) and a = y-bar - b(x-bar). you can get sy, sx, x-bar and y-bar by putting the values into a calculator. R can be gotten using Excel or by hand with a long, tedious formula

For multiple linear regression, it's best to use Excel or use this online calculator for multiple regression, simply put in the values for the x variables and the y variable and you will the result you need

http://www.xuru.org/rt/MLR.asp#Manually

Remember that a multiple linear regression equation will take on the form y^ = a + b0x1 + b1x2 and so on.