The area of the triangle above is 21. What is the value of x ?

Mathematics

1 answer:

Veronika [31]3 years ago

8 0

Answer:

Step-by-step explanation:

area = ½×base×height

21 = ½(x+1)x

42 = (x+1)x

x² + x - 42 = 0

(x+7)(x-6) = 0

x = -7, 6

-7 is an extraneous solution, so x = 6

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State the domain for the set of points.

sertanlavr [38]

Answer:

the domain is the first number of the 2

5 0

3 years ago

Need help!<br> A. y= -x+2<br> B. y=2x+2<br> C. y=2x-1<br> D. y=5x+2

Anastaziya [24]

Answer:

$\large\boxed{y=5x+2}$

Step-by-step explanation:

$\text{Let:}\\\\k:y=m_1x+b_1\\\\l:y=m_2x+b_2\\\\\text{then}\\\\k\ ||\ l\iff m_1=m_2\\\\k \perp l\iff m_1m_2=-1\to m_2=-\dfrac{1}{m_1}\\\\==================================$

$\text{We have the equation of a line:}\\\\y=-\dfrac{1}{5}x+4\to m_1=-\dfrac{1}{5}\\\\\text{Therefore}\\\\m_2=-\dfrac{1}{-\frac{1}{5}}=-\left(-\dfrac{5}{1}\right)=5\\\\\text{Initially, our equation has the form}\\\\y=5x+b$

$\text{The line should pass through point (-1, -3).}\\\text{We substitute the coordinates of the point into the equation:}\\\\-3=5(-1)+b\\-3=-5+b\qquad\text{add 5 to both sides}\\-3+5=-5+5+b\\2=b\to b=2\\\\\text{Finally:}\\\\y=5x+2$