Thread: I do not comprehend Algebra

I have some problems with algebra - I don't get i. Util I get a tutor I am seekig some help here. I have tried several times to get the answers for my homework.
1. The amount of simple interest I generated by principal P, annual interest rate r, and time t in years is given by I=Prt. Find the interest if t=6 years, P=$190, and r=0.08.

2.6[7^2+2(5+5)]

Any help in the right direction would be appreciated.
Thanks so much.

Originally Posted by metromets

I have some problems with algebra - I don't get i. Util I get a tutor I am seekig some help here. I have tried several times to get the answers for my homework.
1. The amount of simple interest I generated by principal P, annual interest rate r, and time t in years is given by I=Prt. Find the interest if t=6 years, P=$190, and r=0.08.

2.6[7^2+2(5+5)]

Any help in the right direction would be appreciated.
Thanks so much.

For the first one, you're plugging the values they give you for t, P, and r...I am not sure what you don't understand for this one.

For the second one,

6*[7^2+2*(5+5)]

PEMDAS: (order of operation rules)...parentheses, exponents, multiplication, division, addition/subtraction...

5+5 = 10 * 2 = 20 + (7^2)

20 + (49) = 69*6

= 414.

Originally Posted by metromets

The amount of simple interest I generated by principal P, annual interest rate r, and time t in years is given by I=Prt. Find the interest if t=6 years, P=$190, and r=0.08.

I = Prt

I = ($190)(0.08)(6)

I = ($190)(0.48)

I = $91.20

-Dan

Originally Posted by AfterShock

For the first one, you're plugging the values they give you for t, P, and r...I am not sure what you don't understand for this one.

For the second one,

6*[7^2+2*(5+5)]

PEMDAS: (order of operation rules)...parentheses, exponents, multiplication, division, addition/subtraction...

5+5 = 10 * 2 = 20 + (7^2)

20 + (49) = 69*6

= 414.

Ummmm...I would leave this one alone except that you are stepping all over one of my pet-peeves!!

For example:

5+5 = 10 * 2 = 20 + (7^2)

What the heck? 5 + 5 = 10. That's it. Not "10*2" because that's equal to 20, which doesn't equal 10.
Please don't do this on tests. It's annoying to try to grade!
End of pet-peeve.

However anal I am about how Aftershock wrote it, he (I'm assuming "he") is correct about order of operations. Let me repeat his argument step by step.

6[7^2+2(5+5)]
Start with the inner-most parenthesis:
6[7^2+2(10)]
Now do exponents before anything else:
6[49+2(10)]
Multiplication before addition:
6[49+20]
Inside the parenthesis first:
6[69]
Finally:
414

-Dan

For the 1st one, I just need some direction in how to set it up. I am so bad!! with that. Once I get going I am all right.

Thank you for the super response, I really appreciate it. I see where I was going wrong. I am eager to be able to understand alegbra! Thank Goodness my Major is English, I can do only basic math! Anyway, thank you both.

Originally Posted by topsquark

Ummmm...I would leave this one alone except that you are stepping all over one of my pet-peeves!!

For example:

What the heck? 5 + 5 = 10. That's it. Not "10*2" because that's equal to 20, which doesn't equal 10.
Please don't do this on tests. It's annoying to try to grade!
End of pet-peeve.

However anal I am about how Aftershock wrote it, he (I'm assuming "he") is correct about order of operations. Let me repeat his argument step by step.

6[7^2+2(5+5)]
Start with the inner-most parenthesis:
6[7^2+2(10)]
Now do exponents before anything else:
6[49+2(10)]
Multiplication before addition:
6[49+20]
Inside the parenthesis first:
6[69]
Finally:
414

-Dan

I think it's quite obvious that when I say 5 + 5 = 10 * 2 = 20, I am meaning to take the result of 5 + 5 and multiply it by 2 to get the new result (20). This isn't a 200, 300, or even a 400 level math course at higher institution. If this was for analytical algebra, or complex analysis, where technicality mattered, then I would agree with you.

Originally Posted by metromets

Thank you for the super response, I really appreciate it. I see where I was going wrong. I am eager to be able to understand alegbra! Thank Goodness my Major is English, I can do only basic math! Anyway, thank you both.

Actually I usually try to teach my students algebra by making analogies to language. For example, if we have "3 + 4" I ask what the Mathematical "dictionary" says this statement means. (And if needed I'll pull out the number line and explain addition in terms of that.) I have found the technique rather useful in breaking problems down into simpler steps.

-Dan