Solve a Linear Equation

Create a function that returns the value of x (the "unknown" in the equation). Each equation will be formatted like this:

x + 6 = 12

Examples

solve("x + 43 = 50") ➞ 7

solve("x - 9 = 10") ➞ 19

solve("x + 300 = 100") ➞ -200

Notes

• "x" will always be in the same place (you will not find an equation like 6 + x = 12).
• Every equation will include either subtraction (-) or addition (+).
• "x" may be negative.