when you have
ax^2+bx+c=0
x=\(\frac{-b+/- \sqrt{b^{2}-4ac} }{2a}\)
1x^2+4x=7
minus 7
1x^2+4x-7=0
a=1
b=4
c=-7
sub
x=\(\frac{-4+/- \sqrt{4^{2}-4(1)(-7)} }{2(1)}\)
x=\(\frac{-4+/- \sqrt{16+28} }{2}\)
x=\(\frac{-4+/- \sqrt{44} }{2}\)
x=\(\frac{-4+/- 2\sqrt{11} }{2}\)
x=\(-2+/- \sqrt{11}\)
x=\(-2+ \sqrt{11}\) or \(-2- \sqrt{11}\)
