Question 201311
Let x=son's age
Then x+5=daughter's age
8x=father's age
Also 4(x+5)=father's age, so:
8x=4(x+5) get rid of parens
8x=4x+20  subtract 4x from each side
8x-4x=4x-4x+20
4x=20  divide each side by 4
x=5--------------son's age
x+5=5+5=10 daughter's age
8x=8*5=40-----------father's age

CK
8*5=4(5+5)
40=40


Hope this helps----ptaylor