<span>let x be the interval, then:
186 = 50 + 3 + (3+x) + (3+2x) + (3+3x) + (3+4x) + (3+5x) + (3+6x) + (3+7x)
186 = 74 + 28x
x = 4
Eldest son age = 3+7x = 3+28 = 31.</span>
Subtract g add 1 divide by 2a
(2, 12)
Because that is where the graphs intersect.
