Cool thanks bro I appreciate it
It’s d because the slope is negative and it is 2/1 which can also be written as just 2. in the formula y=mx+b, m is the slope and b is the y-intercept. the y-intercept is where the line touches the y axis(in this case -1) so it would be written as y=2x+(-1)
You cannot add row 2 to column 3 because they have different dimensions. You can do any of the other operations, but the only one that makes any sort of sense is ...
Multiply row 2 by -1 and add it to row 3
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It makes no sense to multiply a row by zero. That makes the entire row zero and makes the matrix useless for finding any sort of solution.
You can switch columns, but that doesn't get you any closer to a solution here.
If I were trying to find a solution, I might
switch rows 1 and 2
multiply the new row 1 by -3 and add it to the new row 2
multiply the new row 1 by 2 and add it to row 3
This sequence of operations will make the first column [1 0 0], reducing the problem to 2×2 from 3×3.
1). the submarine is descending 100 feet per minute. this is because the line decreases 100 on the y axis when the x axis increases by 1.
2). the submarine is descending 50 feet per minute. this is because the line decreases 50 on the y axis when the x axis increases by 1.
3). y=15x this is because the slope increases by 15 on the y axis when 1 is increased on the x axis. the y intercept is 0. this means that every hour of piano lessons they get paid $15.
I hope this helps, and hopefully I’m right :)