The dimension of ab in the equation P=a−t2bx,where P is pressure, x is distance and t is time, is
MT−2
M2LT−3
ML3T−1
LT−3
[a]=T2 and [b]=a−t2[P][x]=T2ML−1T−2[L]
⇒ [b]=M−1T4 So ab=T2M−1T4=MT−2