Answer:
Step-by-step explanation:
Obviously, we are letting u = x + 2. So what we have when we rewrite using this substitution is
[tex]u^2+12u-14=0[/tex] and we plug that into the quadratic formula with
a = 1, b = 12, c = -14:
[tex]u=\frac{-12+-\sqrt{12^2-4(1)(-14)} }{2(1)}[/tex] which can be simplified to
[tex]u=\frac{-12+-\sqrt{144+56} }{2}[/tex] and a bit more to
[tex]u=\frac{-12+-\sqrt{200} }{2}[/tex] and a tiny bit more to
[tex]u=\frac{-12+-10\sqrt{2} }{2}[/tex] and finally to
[tex]u=-6+-5\sqrt{2}[/tex] and plug back in for u:
x + 2 = -6 ± 5√2 and then subtract the 2 to get
x = -8 ± 5√2
