To start:
1 - You would have to get rid of the square root on the left side of the equation by squaring both sides leaving you with 3x + 4 = x^2
2 - You then set the equation equal to 0 by moving 3x + 4 to the same side as x^2. Leaving you with x^2 - 3x - 4.
3 - Finally, you solve the equation by finding the factors of the equation, in this case there are two as the highest exponent is 2:
(x - 4) * (x + 1) - These work as if you were to multiply them together again, you get the second equation as seen in step 2.
4 - Final Answer:
x = 4, -1
NOTE: We know these numbers are correct as when we plug them back into the equation, they produce the right numbers