Answer:
If you're in Alg 1 or IM 1 like 7th-9th grade or so the answer maybe "no solution" If you're in Alg2 or IM2 or IM3 you can solve this. See image.
Explanation:
Get the variable by itself by subtracting 49 from both sides. Use the fact that the sqrt of -1 is the imaginary number, i (yes, in math the imaginary number is a real thing, lol)