Answer:
R=-33
Step-by-step explanation:
Since you need an isolated variable to use the substitution method, we need to re-arrange one of the equations. This will probably be easiest to do with the first one.
Add 5y to both sides of the first equation.
x=10+5y
Now, in the second equation, put in 10+5y in any spot that has an x.
2(10+5y)-10y=20
Distribute the 2 to both numbers in the parenthesis.
20+10y-10y=20
Combine like terms.
20=20
This means that the two equations are actually the same. You can see this if you multiply the whole first equation by 2
2(x-5y=10)
2x-10y=20, which is the same as the second equation. Therefore, the two equations are actually the same one.
That is permuations
that would be 10! or 10*9*8*7*6*5*4*3*2*1=3628800 ways
"Understand the problem" might rightly consist of
• Perform this step first
• Identify what you are being asked to solve or find.
• Identify the important words or numbers in the problem
• Identify any instructions that you are supposed to follow
_____
One of my professors always insisted we start the solution of any problem by writing down what was Given, and what we had to Find, using those headers for the sections of the paper we turned in. Only after those were listed were we allowed to write the Solution. Solution papers that didn't have that format were tossed in the trash, and no credit was given. Harsh, but effective.
