All categories

3 years ago

M

Mathematics

1 answer:

Ierofanga [76]3 years ago

4 0

Answer:

see below

Step-by-step explanation:

m/3 + 4 = 7

Subtract 4 from each side

m/3+4-4 = 7-4

m/3 = 3

Multiply each side by 3

m/3*3 = 3*3

m =9

You might be interested in

Pls help me I’ll give out brainliest please dont answer if you don’t know

nlexa [21]

Step-by-step explanation:

x=-10 is ur answer try it!

6 0

3 years ago

Read 2 more answers

Solve for XX. Assume XX is a 2×22×2 matrix and II denotes the 2×22×2 identity matrix. Do not use decimal numbers in your answer.

sveticcg [70]

The question is incomplete. The complete question is as follows:

Solve for X. Assume X is a 2x2 matrix and I denotes the 2x2 identity matrix. Do not use decimal numbers in your answer. If there are fractions, leave them unevaluated.

$\left[\begin{array}{cc}2&8\\-6&-9\end{array}\right]$ · X· $\left[\begin{array}{ccc}9&-3\\7&-6\end{array}\right]$ =I.

First, we have to identify the matrix I. As it was said, the matrix is the identiy matrix, which means

I = $\left[\begin{array}{ccc}1&0\\0&1\end{array}\right]$

So, $\left[\begin{array}{cc}2&8\\-6&-9\end{array}\right]$ · X· $\left[\begin{array}{ccc}9&-3\\7&-6\end{array}\right]$ = $\left[\begin{array}{ccc}1&0\\0&1\end{array}\right]$

Isolating the X, we have

X· $\left[\begin{array}{ccc}9&-3\\7&-6\end{array}\right]$ = $\left[\begin{array}{cc}2&8\\-6&-9\end{array}\right]$ - $\left[\begin{array}{ccc}1&0\\0&1\end{array}\right]$

Resolving:

X· $\left[\begin{array}{ccc}9&-3\\7&-6\end{array}\right]$ = $\left[\begin{array}{ccc}2-1&8-0\\-6-0&-9-1\end{array}\right]$

X· $\left[\begin{array}{ccc}9&-3\\7&-6\end{array}\right]$ = $\left[\begin{array}{ccc}1&8\\-6&-10\end{array}\right]$

Now, we have a problem similar to A.X=B. To solve it and because we don't divide matrices, we do X=A⁻¹·B. In this case,

X= $\left[\begin{array}{ccc}9&-3\\7&-6\end{array}\right]$ ⁻¹· $\left[\begin{array}{ccc}1&8\\-6&-10\end{array}\right]$

Now, a matrix with index -1 is called Inverse Matrix and is calculated as: A . A⁻¹ = I.

So,

$\left[\begin{array}{ccc}9&-3\\7&-6\end{array}\right]$ · $\left[\begin{array}{ccc}a&b\\c&d\end{array}\right]$ = $\left[\begin{array}{ccc}1&0\\0&1\end{array}\right]$

9a - 3b = 1

7a - 6b = 0

9c - 3d = 0

7c - 6d = 1

Resolving these equations, we have a= $\frac{2}{11}$ ; b= $\frac{7}{33}$ ; c= $\frac{-1}{11}$ and d= $\frac{-3}{11}$ . Substituting:

X= $\left[\begin{array}{ccc}\frac{2}{11} &\frac{-1}{11} \\\frac{7}{33}&\frac{-3}{11} \end{array}\right]$ · $\left[\begin{array}{ccc}1&8\\-6&-10\end{array}\right]$

Multiplying the matrices, we have

X= $\left[\begin{array}{ccc}\frac{8}{11} &\frac{26}{11} \\\frac{39}{11}&\frac{198}{11} \end{array}\right]$

6 0

3 years ago

if alyssa plans to run 7/8 mile on a trail at one point she sees that she is at mile maker 0.3 How much farther does she have to

Sever21 [200]

Rewrite 7/8 as a decimal by dividing 7 by 8:

7/8 = 0.875

Now to find how much further she has to run subtract where is now from the total distance:

0.875 - 0.3 = 0.575

She needs to run 0.575 miles more

6 0

2 years ago

Find the greatest common factor of these three expressions.

leva [86]

6x

42/6 = 7 (valid), 18/6 = 3 (valid), 12/6 = 2 (valid)

7, 8, 9, 10, and 11 are all not divisible by 12, and 12 is not divisible by 18, so 6 is the highest number.

Also, each number has at least one x, so you can take one out.

Remaining=
6x (7 + 3x^2 + 2x^3)

3 0

3 years ago

Dexter had 15 fish in the fish tank. 7 were goldfish and the rest were neon tetra fish. Then he added 4 neon tetra fish. How man

Evgesh-ka [11]

Answer:

answer is 12

Step-by-step explanation:

if you take 15 and subtract it by 7 that would give you the number of neon tetra fish, then you can add 4 to give you your total number which is 12 :)

7 0

3 years ago