Use the quadratic formula to solve x2 + 7x + 8 = 0. Estimate irrational solutions to the nearest tenth.


{–12, 5}

{–11.1, –2.9}

{–5.6, –1.4}

{–3.9, 12.1}

Respuesta :

Answer:

{–5.6, –1.4}

Step-by-step explanation:

The quadratic formula is [tex]x=\frac{-b+/-\sqrt{b^2-4ac} }{2a}[/tex]. Here a=1, b=7, and c=8.

Substitute and you'll have:

[tex]x=\frac{-b+/-\sqrt{b^2-4ac} }{2a} =\frac{-7+/-\sqrt{7^2-4(1)(8)} }{2(1)}=\frac{-7+/-\sqrt{49-32} }{2)}[/tex]

[tex]\frac{-7+/-\sqrt{17} }{2}[/tex]

This approximates as:

[tex]\frac{-7 + 4.123}{2} , \frac{-7 - 4.123}{2} \\\\\frac{-3.123}{2} , \frac{-11.123}{2}\\-1.6, -5.6[/tex]