Please help! Find the value of c in the isosceles trapezoid.

makkiz [27]

$\left[\begin{array}{ccc}9&7\\-4&2\end{array}\right] -4M=\left[\begin{array}{ccc}-3&3\\4&-18\end{array}\right]\qquad(*) \\\\M=\left[\begin{array}{ccc}a&b\\c&d\end{array}\right]\to4M=\left[\begin{array}{ccc}4a&4b\\4c&4d\end{array}\right]$

$(*)\qquad\left[\begin{array}{ccc}9&7\\-4&2\end{array}\right] -\left[\begin{array}{ccc}4a&4b\\4c&4d\end{array}\right]=\left[\begin{array}{ccc}-3&3\\4&-18\end{array}\right]\\\\\left[\begin{array}{ccc}9-4a&7-4b\\-4-4c&2-4d\end{array}\right]=\left[\begin{array}{ccc}-3&3\\4&-18\end{array}\right]\\.\qquad\qquad\qquad\qquad\ \ \ \Downarrow\\(_{11})\qquad9-4a=-3\ \ \ |-9\\-4a=-12\ \ \ \ |:(-4)\\a=3\\\\(_{12})\qquad7-4b=3\ \ \ \ |-7\\-4b=-4\ \ \ \ |:(-4)\\b=1$

$(_{21})\qquad-4-4c=4\ \ \ \ |+4\\-4c=8\ \ \ \ |:(-4)\\c=-2\\\\(_{22})\qquad2-4d=-18\ \ \ \ |-2\\-4d=-20\ \ \ \ \ |:(-4)\\d=5\\\\Answer:\ A.\ M=\left[\begin{array}{ccc}3&1\\-2&5\end{array}\right]$

3 0

3 years ago

Find the domain of the following relation. <br> R={(19,96),(20,101),(21,106),(22,111)}

mafiozo [28]

(x, y)

The domain are all the x-values, the range are all the y-values.

R={(19,96),(20,101),(21,106),(22,111)}

The domain is: 19, 20, 21, and 22
The range is: 96, 101, 106, and 111

7 0

3 years ago

Read 2 more answers

6 labour complete a work in 12 days. How many labours should added to complete the works in 8 days?

mario62 [17]

Answer:

9 labours

Step-by-step explanation:

In order to solve this, we must know which kind of proportionality is this. There are two types of proportions, direct and indirect/inverse proportions. In direct proportion, if one quantity increases, the other quantity also increases.

In indirect proportion, if one quantity increases, the other decreases and vice versa.

As per this question, we know if the number of labour increases, the number of days to complete a work decreases, thus proving that this is an indirect/inverse proportion.

6 labours => 12 days

x labours => 8 days

Since its an inverse proprotion, multiply 6 with 12, and x with 8.

8x = 6 × 12

x = $\frac{6*12}{8}$

∴ x = <u>9 labours</u>

7 0

2 years ago

A principal of $835 is invested in an account at 4% per quarter simple interest which of the following sequences describes the d

netineya [11]

To solve the question we use the compound interest formula which is given by:
A=p(1+r)^(nt)
where:
A=future value
p=principle
r=rate
n=number of terms
t=time
thus plugging in the values in the formula we shall have:
A=835(1+0.04)^(4t)
simplifying this we get the sequence:
A=835(1.040)^(4t)
Thus the answer to the sequence will be:
A=835(1.040)^(4t)

7 0

3 years ago

Which vector matrix represents the reflection of the vector <-1,5> across the line x = y

Arturiano [62]

Answer:

$V = \left[\begin{array}{ccc}5&-1\end{array}\right]$

Step-by-step explanation:

We want to reflect this 2x1 vector on the line y = x.

To make this reflection we must use the following matrix:

$R=\left[\begin{array}{cc}0&1\\1&0\\\end{array}\right]$

Where R is known as the reflection matrix on the line x = y

Now perform the product of the vector <-1,5> x R.

$\left[\begin{array}{ccc}-1\\5\end{array}\right]x\left[\begin{array}{ccc}0&1\\1&0\end{array}\right]\\\\\\\left[\begin{array}{ccc}-1(0) +5(1)&-1(1)+5(0)\end{array}\right]\\\\\\\left[\begin{array}{ccc}5&-1\end{array}\right]$

The vector matrix that represents the reflection of the vector <-1,5> across the line x = y is:

$V = \left[\begin{array}{ccc}5&-1\end{array}\right]$

6 0

3 years ago