1.x^2 +6x - 4 = 6x
X^2 + 6x -4 - 6x = 0
X^2 - 4 = 0
By difference of two squares :
X^2 - 4 = 0 can be written as (x-2) (x+2) = 0
(X-2)=0 therefore x= 2

(X+2)=0 therefore x= -2

2. X^2 - 8x = -6x
X^2 -8x + 6x = 0
X^2 - 2x = 0
X(X-2) = 0
X= 0, X= 2

6 0

2 years ago

Compute a · (b ✕ c), where a = i − 3j + k, b = 4i + j + k and c = 9i − j + 3k.

grandymaker [24]

$\mathbf a=\mathbf i-3\,\mathbf j+\mathbf k$
$\mathbf b=4\,\mathbf i+\mathbf j+\mathbf k$
$\mathbf c=9\,\mathbf i-\mathbf j+3\,\mathbf k$

$\mathbf b\times\mathbf c=\begin{vmatrix}\mathbf i&\mathbf j&\mathbf k\\4&1&1\\9&-1&3\end{vmatrix}=4\,\mathbf i-3\,\mathbf j-13\,\mathbf k$

$\mathbf a\cdot(\mathbf b\times\mathbf c)=(\mathbf i-3\,\mathbf j+\mathbf k)\cdot(2\,\mathbf i-3\,\mathbf j-13\,\mathbf k)=4+(-3)^2-13=0$

6 0

2 years ago

38.Randy and Amy left school at the same time and began walking in oppo-

RideAnS [48]

Answer:

DISTANCE=RATE*TIME. THEREFORE

X=3.6*1/6+4.2*1/6 (1/6 HOUR=10 MIN)

X=.6+.7

X=1.3 KM IS HOW FAR THEY WIL BE APART AFTER 10 MINUTES.

Step-by-step explanation:

7 0

2 years ago

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