Answer:
Step-by-step explanation:
5.(a)
x²+6x-15=0
[tex]x=\frac{-6\pm\sqrt{36+4*15}}{2*1}\\x=\frac{-6\pm\sqrt{36+60} }{2}\\x=\frac{-6\pm\sqrt{96} }{2}\\x=\frac{-6\pm4\sqrt{6} }{2}\\x=-3\pm2\sqrt{6}[/tex]
(b)
4x²-8x-1=0
[tex]x=\frac{8\pm\sqrt{64+4*4}}{2*4}\\x=\frac{8\pm\sqrt{80}}{8}\\x=\frac{8\pm 4\sqrt{5} }{8}\\x=\frac{2\pm\sqrt{5}}{2}[/tex]
