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3 years ago

HELP! Which is the inverse of this matrix?

Mathematics

1 answer:

malfutka [58]3 years ago

7 0

Answer:

$\text{\bf{A.}}\qquad\left[\begin{array}{ccc}-19&9&-7\\15&-7&6\\-2&1&-1\end{array}\right]$

Step-by-step explanation:

Many scientific and graphing calculators will compute this easily.

The inverse of a square matrix is a square matrix of the same dimensions. That eliminates choices C and D. We can check choices A and B by computing a couple of terms of the product of the given matrix and its "inverse". That product should be the identity matrix, with 1 on the diagonal and 0 elsewhere.

Using matrix A,

(r, c) = (1, 1) = 1(-19) +2(15) +5(-2) = -19 +30 -20 = 1 . . . . correct

(r, c) = (2,3) = 3(-7) +5(6) +9(-1) = -21 +30 =9 = 0 . . . . correct

Using matrix B,

(r, c) = (1, 1) = 1(-19) +2(-2) +5(15) = -19 -4 +75 = 52 . . . . incorrect

Indications are that choice A is appropriate.

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Please help asap thx :)

OleMash [197]

Step-by-step explanation:

the average rate of change is

(f(x2) - f(x1)) / (x2 - x1)

so, for x = 1 and 2

(4×3² - 4×3¹) / (2 - 1) = 36 - 12 = 24

for x = 3 and 4

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5 0

3 years ago

Mia is helping her glee club raise money to fund a field trip. The glee club secided to sell pencils, which come in boxes of 100

Nitella [24]

Answer:

m = 2500b

Step-by-step explanation:

As instructed,

let b = number of boxes sold

let m = total money made.

The total money made, is a function of the number of boxes sold.

Let me break this down:

There are 100 pencils in a box;

if they sold only one box, they will get 100 X $25 = $2500;

if they sold two boxes, they will get 200 X $25 = $5000;

if they sold three boxes, they will get 300 X $25 = $7500;

Following the trend, we can deduce that money made, m = (number of boxes sold X 100 ) X $25

representing this using the variables we were given, we have

m = 100b X 25

hence

m = 2500b

7 0

3 years ago

A set of weights includes a 10 lb barbell and 8 pairs of weight plates. Each pairof plates weighs 20lbs. If x pairs of plates ar

Leni [432]

It is given that the weight of the barbel is given by:

$f(x)=20x+10$

It says that there are eight pair of weights so x can take values from 0 to 8 and f(x) can take the values as follows:

$\begin{gathered} x=0,f(x)=10 \\ x=1,f(x)=30 \\ x=2,f(x)=50 \\ x=3,f(x)=70 \\ x=4,f(x)=90 \\ x=5,f(x)=110 \\ x=6,f(x)=130 \\ x=7,f(x)=150 \\ x=8,f(x)=170 \end{gathered}$

So the range is: