THIS THE 3RD EQUATION OF MOTION.
v2 - u2 = 2as
Let us consider an object moving with an initial velocity = u ms-1 , final velocity = v ms-1 , with an acceleration = a ms-2 , in time = t sec
we know , velocity = distance
time
v = s therefore , s = vt - (1)
t
vavg = u + v - (2)
2
Substitute the value of v from equation (2) in equation (1)
s = (u + v ) t - (3)
2
But by equation of motion : v = u + at
t = v - u - (4)
a
Substitute the value of t from equation (4) in equation (3)
s = u + v X v - u
2 a
s = uv - u2 + v2 - uv
2a
2as = - u2 + v2
therefore, v2 - u2 = 2as
