First you need to make both bases the same:
Lets remove the ^p and ^4
To make the base of 42 equal to 41, you would have 41^x = 41
X - ln(42) / ln(41) = 1.00648904
Now you have 41^1.00648904(p) = 41^4
Now the bases are equal so we need to set the exponents to equal:
1.00648904(p) = 4
Divide both sides by 1.00648904 to solve for P
P = 4 / 1.00648904
P = 3.97421114