Question

Solve using the quadratic formula x2 - 6x - 40=0 Question options: x = 10 or x = -4 x = 4 or x = -10 x = -7 or x = 7 x = -4 - √7 or x = -4 + √7 solve for x the find angle b

Answer 1

Always try to show the FOIL (first outer inner last) breakout if you can.

Think of the factors of 40 - fortunately only a few options come to mind.

10x4 and 8x5

Knowing the “inner” term is 6, this means the factors are 4 and 10 because 10-4=6

The inner term is negative, so the first term must have a -10 in it.


Therefore:

(x-10)*(x+4)=0

Or

X = 10

X = -4

Answer 2

Answer:

$x=-10$ or $x=4$

Step-by-step explanation:

$ax^2+bx+c=0$

$x^2-6x-40=0$

$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$

$x=\frac{-6\pm\sqrt{6^2-4(1)(-40)}}{2(1)}$

$x=\frac{-6\pm\sqrt{36+160}}{2}$

$x=\frac{-6\pm\sqrt{196}}{2}$

$x=\frac{-6\pm14}{2}$

$x=-3\pm7$

$x=-10$ or $x=4$