Yes, the rules of scientific notation are:
1. All non-zero digits are significant
2. Zeros in between non-zeros are significant.
3. Zeros to the left of the first non-zero number are NOT significant.
4. Zeros to the right of non-zero numbers are significant IF a decimal point is present.
P.S: if you need help with sig fig rounding, let me know.
For this case we have the following system of equations:

We observe that we have a quadratic equation and therefore the function is a parabola.
We have a linear equation.
Therefore, the solution to the system of equations will be the points of intersection of both functions.
When graphing both functions we have that the solution is given by:

That is, the line cuts the quadratic function in the following ordered pair:
(x, y) = (1, 2)
Answer:
the solution (s) of the graphed system of equations are:
(x, y) = (1, 2)
See attached image.
7 + 2x = 51
hope this helps