A=1x3 means 1 row and 3 columns.
B=3x4 means 3 rows and 4 columns.
AB is a compatible multiplication because A has three columns and B has 3 rows.
However, BA is not a compatible multiplication because B has 4 columns while A has only 1 row.
The general trick is if you read the row/column of the two matrices as 1-3-3-4, and the two middle ones are identical, then AB would be a compatible multiplication. On the other hand, BA would read 3-4-1-3, since 4 and 1 are not identical, so it is not a valid multiplication.
Do remember 1x3 means 1 ROW and 3 COLUMNS.
Answer:
The best and most correct answer among the choices provided by your question is the third choice or letter C. The total number of hours is 17.
For h>7
C=210+20(h-7)
C=210+20h-140
C=20h+70, h>7
410=20h+70
20h=340
h=17 hours
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When we solve the equation, we will get the real answer <u>x=40</u> as a variable.
<h3>First Degree Equation</h3>
First degree equation is a mathematical sentence, which has values represented by letters.
These letters can indicate a variable or an unknown - which at the end of the equation will be the final value.
— To solve this equation, just: apply the distributive property (multiply the terms that are outside the parentheses, for the terms that are inside the symbol).
— Next, let's add the real numbers together. Next, we'll subtract the like terms before the equality, thus moving the common term after the equality by adding.
— Finally, let's divide the equation, thus obtaining the final result.
4 + 3(x + 22) = 5x - 10
4 + 3x + 66 = 5x - 10
70 + 3x = 5x - 10
3x - 5x = -10 - 70
-2x = -80
x = 80 ÷ 2
<u>x = 40</u>
Therefore, the correct value of X in this equation, will be <u>x = 40</u>.
You use the equation Ax^2 + Bx + C to solve this equation.
The answer is 25.
I hope this helps :D