Mathematics, 12.03.2020 00:03 irenecupcake3467

If A= and B= Find BA.

Answers: 3

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Answers

Answer from: jermainedwards

Option B:

$BA=\left(\begin{array}{ccc}37 & 55 & -20 \\23 & 11 & -20 \\25 & 28 & -9\end{array}\right)$

Solution:

Given data:

$A=\left[\begin{array}{ccc}1 & 7 & -3 \\5 & 2 & 1 \\-1 & 2 & -4\end{array}\right]$

$B=\left[\begin{array}{ccc}5 & 7 & 3 \\-3 & 7 & 9 \\2 & 5 & 2\end{array}\right]$

To find BA:

Multiply the rows of the first matrix by the columns of the second matrix.

$\left(\begin{array}{ccc}5 & 7 & 3\end{array}\right)\left(\begin{array}{c}1 \\5 \\-1\end{array}\right)=5 \cdot 1+7 \cdot 5+3(-1)$

$\left(\begin{array}{lll}5 & 7 & 3\end{array}\right)\left(\begin{array}{l}7 \\2 \\2\end{array}\right)=5 \cdot 7+7 \cdot 2+3 \cdot 2$

$\left(\begin{array}{lll}5 & 7 & 3\end{array}\right)\left(\begin{array}{c}-3 \\1 \\-4\end{array}\right)=5(-3)+7 \cdot 1+3(-4)$

$\left(\begin{array}{ccc}-3 & 7 & 9\end{array}\right)\left(\begin{array}{c}1 \\5 \\-1\end{array}\right)=(-3) \cdot 1+7 \cdot 5+9(-1)$

$\left(\begin{array}{lll}-3 & 7 & 9\end{array}\right)\left(\begin{array}{l}7 \\2 \\2\end{array}\right)=(-3) \cdot 7+7 \cdot 2+9 \cdot 2$

$\left(\begin{array}{ccc}-3 & 7 & 9\end{array}\right)\left(\begin{array}{c}-3 \\1 \\-4\end{array}\right)=(-3)(-3)+7 \cdot 1+9(-4)$

$\left(\begin{array}{lll}2 & 5 & 2\end{array}\right)\left(\begin{array}{c}1 \\5 \\-1\end{array}\right)=2 \cdot 1+5 \cdot 5+2(-1)$

$\left(\begin{array}{lll}2 & 5 & 2\end{array}\right)\left(\begin{array}{l}7 \\2 \\2\end{array}\right)=2 \cdot 7+5 \cdot 2+2 \cdot 2$

$\left(\begin{array}{lll}2 & 5 & 2\end{array}\right)\left(\begin{array}{c}-3 \\1 \\-4\end{array}\right)=2(-3)+5 \cdot 1+2(-4)$

$BA=\left(\begin{array}{ccc}5 \cdot 1+7 \cdot 5+3(-1) & 5 \cdot 7+7 \cdot 2+3 \cdot 2 & 5(-3)+7 \cdot 1+3(-4) \\(-3) \cdot 1+7 \cdot 5+9(-1) & (-3) \cdot 7+7 \cdot 2+9 \cdot 2 & (-3)(-3)+7 \cdot 1+9(-4) \\2 \cdot 1+5 \cdot 5+2(-1) & 2 \cdot 7+5 \cdot 2+2 \cdot 2 & 2(-3)+5 \cdot 1+2(-4)\end{array}\right)$ Simplify each element.

$BA=\left[\begin{array}{ccc}5+35-3&35+14+6&-15+7-12\\-3+35-9&-21+14+18&9+7-36\\2+25-2&14+10+4&-6+5-8\end{array}\right]$

$BA=\left(\begin{array}{ccc}37 & 55 & -20 \\23 & 11 & -20 \\25 & 28 & -9\end{array}\right)$

Hence option C is the correct answer.

Answer from: Quest

the system of inequity is

$y\leq -x+4$

$3y> x$

step-by-step explanation:

from the given graph it is noticed that we have two related lines. one is solid and another is dashed.

if a line passing through two points, then the equation of line is

$y-y_1=\frac{y_2-y_1}{x_2-x_1}(x-x_1)$

the solid line passing through the points (0,4) and (4,0).

$y-4=\frac{0-4}{4-0}(x-0)$

$y=-x+4$

the related equation of solid line is $y=-x+4$ .

similarly, find the related equation of dashed line. the dashed liune passing through the points (0,0) and (3,1).

$y-0=\frac{0-1}{3-0}(x-0)$

$3y=x$

the related equation of dashed line is $3y=x$

from the given graph it is noticed that the point (0,1) lies on the shaded region, therefore the point (0,1) must be satisfied by the related equations.

check the related equations by the point (0,1).

$1=-0+4$

$1=4$

this statement is true if the sign of inequality is < instead of equality. since it is an solid line therefore the sign of inequality will be $\leq$ . the required inequality is

$y\leq -x+4$

similarly, check the second related equation.

$3(1)=0$

it is a dashed line, so this statement is true if the sign of inequality is > . the required inequality is

$3y> x$

15 points write a system of inequalities to represent the shaded portion of the graph

Answer from: Quest

9) i can't see the angle so whatever it is just do this: cos(angle) x hypotenuse and then use that answer and they hypotenuse and plug it into this: (answer you just got)^2 + b^2 = (hypotenuse)^2. the first answer will be the answer of the adjacent side and the second answer after this equation will be the opposite side.

10) y = 14 x = √147 or 12.12435565

11) x = 4.8

12) x = 4.2

13) x = 9.3

14) pq: 13.2

qr : 17.6

angle p: 53º

15) angle c: 54.3º

angle a: 35.7º

16) h = 21040

v = 1841

step-by-step explanation:

10) 7/sin(30) = 14 = y

7^2 + b^2 = 14^2

49 + b^2 = 196

b^2 = 196 - 49

√b^2 = √147

x = √147

11) cos(70) x 14 = 4.788282007

x = 4.8

12) tan(25) x 9 = 4.196768923

x = 4.2

13) sin(31) x 18 = 9.270685348

x = 9.3

14) pq: sin(37) x 22 = 13.23993051

pq: 13.2

qr: cos(37) x 22 = 17.56998122

qr : 17.6

angle p: 180 - (37 + 90) = 53º

15) cos-1(7/12) = 54.31466529

angle c: 54.3º

angle a: 180 - (90 + 54.31466529) = 35.68533471

angle a: 35.7º

16) 4 x 5280 = 21120

cos(5) x 21120

h = 21039.63202

h = 21040

sin(5) x 21120

v = 1840.729287

v = 1841

Lots of points! show all of your work! i need #9-#14 and 12 + 16!

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