We can use the quadratic equation to solve this problem:
The quadratic formula states:
For color(red)(a)x^2 + color(blue)(b)x + color(green)(c) = 0, the values of x which are the solutions to the equation are given by:
x = (-color(blue)(b) +- sqrt(color(blue)(b)^2 - (4color(red)(a)color(green)(c))))/(2 * color(red)(a))
Substituting:
color(red)(2) for color(red)(a)
color(blue)(3) for color(blue)(b)
color(green)(7) for color(green)(c) gives:
x = (-color(blue)(3) +- sqrt(color(blue)(3)^2 - (4 * color(red)(2) * color(green)(7))))/(2 * color(red)(2))
x = (-color(blue)(3) +- sqrt(9 - 56))/4
x = (-color(blue)(3) +- sqrt(-47))/4