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Sedaia [141]
2 years ago
14

I forget how to do this problem, little help-?

Mathematics
1 answer:
jenyasd209 [6]2 years ago
4 0

X=4

Please mark brainliest

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Solve the matrix equation for a, b, c, and d. [1 2] [a b] [6 5][3 4] [c d]= [19 8]
Anit [1.1K]

Answer:

The answer is "\bold{\left[\begin{array}{cc}a&b\\c&d\end{array}\right] = \left[\begin{array}{cc}7&-2\\ -\frac{1}{2}&\frac{7}{2}\end{array}\right]}".

Step-by-step explanation:

\bold{\left[\begin{array}{cc}1&2\\3&4\end{array}\right] \left[\begin{array}{cc}a&b\\c&d\end{array}\right] = \left[\begin{array}{cc}6&5\\ 19&8\end{array}\right]}

Solve the L.H.S part:

\left[\begin{array}{cc}1&2\\3&4\end{array}\right] \left[\begin{array}{cc}a&b\\c&d\end{array}\right]\\\\\\\left[\begin{array}{cc}a+2c&b+2d\\3a+4c&3b+4d\end{array}\right]

After calculating the L.H.S part compare the value with R.H.S:

\left[\begin{array}{cc}a+2c&b+2d\\3a+4c&3b+4d\end{array}\right]= \left[\begin{array}{cc}6&5\\ 19&8\end{array}\right]} \\\\

\to a+2c =6....(i)\\\\\to b+2d =5....(ii)\\\\\to 3a+4c =19....(iii)\\\\\to 3b+4d = 8 ....(iv)\\\\

In equation (i) multiply by 3 and subtract by equation (iii):

\to 3a+6c=18\\\to 3a+4c=19\\\\\text{subtract}... \\\\\to 2c = -1\\\\\to  c= - \frac{1}{2}

put the value of c in equation (i):

\to a+ 2 (- \frac{1}{2})=6\\\\\to a- 2 \times \frac{1}{2}=6\\\\\to a- 1=6\\\\\to a =6 +1\\\\\to a = 7\\

In equation (ii) multiply by 3 then subtract by equation (iv):

\to 3b+6d=15\\\to 3b+4d=8\\\\\text{subtract...}\\\\\to 2d = 7\\\\\to d= \frac{7}{2}\\

put the value of d in equation (iv):

\to 3b+4 (\frac{7}{2})=8\\\\\to 3b+4 \times \frac{7}{2}=8\\\\\to 3b+14=8\\\\\to 3b =8-14\\\\\to 3b = -6\\\\\to b= \frac{-6}{3}\\\\\to b= -2

The final answer is "\bold{\left[\begin{array}{cc}a&b\\c&d\end{array}\right] = \left[\begin{array}{cc}7&-2\\ -\frac{1}{2}&\frac{7}{2}\end{array}\right]}".

4 0
3 years ago
Divide using any method. .<br> -3.23 + 4x2 + 2x – 5)<br> 2
stepladder [879]

Answer:

Step-by-step explanation:

-3x^2 --2x--2 -- 9/x--2

3 0
3 years ago
23. Eduardo wants to get a grade of 95 in his math
dem82 [27]

Answer:

105

Step-by-step explanation:

It is easy to calculate: add up all the numbers, then divide by how many numbers there are. In other words it is the sum divided by the count.

(91+89+X)/3 =95

 91+89+X =95*3

180+X =285

X =285 - 180

  =105

7 0
2 years ago
PLEASE HELP ME!!!!!!!!!! 57-4t &gt;(their is an egual sign under the less then sign)13
Alexandra [31]
57 - 4t > = 13.....subtract 57 from both sides
-4t > = 13 - 57
-4t > = - 44 ...divide both sides by -4, and change the inequality sign
t < = -44 / -4
t < = 11

u solve inequalities much like u do equations except for one very important rule. In an inequality, if u divide/multiply by a negative number, u have to change the inequality sign.



8 0
2 years ago
Read 2 more answers
The electrician arrives at Laura's house to fix her broken furnace. The electrician charges 90 dollars for the first hour and 60
tamaranim1 [39]

Answer:

5 hours

Step-by-step explanation:

Electrician got 90 for the first hour from the total bill, thus we can say:

330 - 90 = 240 remaining for remaining hours

$60 per hour, so $240 for how many hours?? We divide:

240/60 = 4 hours

So, electrician works 4 hours for 60 per hour = 2 * 6 = 240

and 1 hour for 90 (first hour) = 1 * 90 = 90

Total Bill is 240 + 90 = 330 {exactly what we have}

So we have checked and back-worked our problem to get electrician's total hours of work:

1 + 4 = 5 hours

7 0
3 years ago
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