=  - 2

Square both sides:


[]² = [ - 2]²

[]² = [ - 2][ - 2]

Use FOIL on the right

[]² = []² - 2 - 2 + 4

[]² = []² - 4 + 4


x-3 = x+15 - 4 + 4

x-3 = x+19 - 4 

-22 = -4

Square both sides again:

(-22)² = [-4]²

484 = 16(x+15)

484 = 16x + 240

244 = 16x 

 = x

 = x

Now we have to check because sometimes there are 
extraneous (phony) solutions to radical equations:

 =  - 2

 =  - 2

Get LCD of 4

 =  - 2

 =  - 2

 =  - 2

 =  - 

 = 

Edwin