**Given Information:**
- Shefali's marks in Mathematics and English sum up to 30.
- If Shefali had scored 2 marks more in Mathematics and 3 marks less in English, the product of their marks would have been 210.

**Let's assume:**
- Shefali's marks in Mathematics = x
- Shefali's marks in English = y

**Formulating Equations:**
1. According to the first condition, the sum of Shefali's marks in Mathematics and English is 30:
x + y = 30

2. According to the second condition, if Shefali had scored 2 marks more in Mathematics and 3 marks less in English, the product of their marks would have been 210:
(x + 2)(y - 3) = 210

**Solving the Equations:**

To find the values of x and y, we need to solve the above two equations.

1. Simplifying Equation 2:
xy + 2y - 3x - 6 = 210
xy - 3x + 2y = 216 (Rearranging the terms)

2. Rearranging Equation 1:
x = 30 - y

3. Substituting x = 30 - y in Equation 2:
(30 - y)y - 3(30 - y) + 2y = 216

Simplifying the equation further:
30y - y^2 - 90 + 3y + 2y = 216
-y^2 + 35y - 90 = 216
-y^2 + 35y - 90 - 216 = 0
-y^2 + 35y - 306 = 0

4. Solving the quadratic equation:
Using the quadratic formula, we can find the values of y:
y = (-b ± √(b^2 - 4ac)) / 2a

Here, a = -1, b = 35, c = -306

y = (-(35) ± √((35)^2 - 4(-1)(-306))) / 2(-1)
y = (-35 ± √(1225 - 1224)) / -2
y = (-35 ± √1) / -2

y = (-35 ± 1) / -2

Therefore, the two possible values for y are:
y1 = (-35 + 1) / -2 = 34 / -2 = -17
y2 = (-35 - 1) / -2 = -36 / -2 = 18

**Calculating the values of x:**

Now that we have the two possible values for y, we can substitute them into Equation 1 to find the corresponding values of x.

1. For y = -17:
x = 30 - y
x = 30 - (-17)
x = 30 + 17
x = 47

Therefore, when y = -17, x = 47.

2. For y = 18:
x = 30 - y
x = 30 - 18
x = 12