Algebra problem---can't figure it out!

[Katie]

We worked last night until late finishing my dd homework( i always check it)

anyway, we both could not figure out the answer for this problem

d(squared)-33d+280=0
solve for d



(d-something)(d-something)


help us!
Ex. d(squared)+5x+6=0
(d+3)(d+2)

thanks

 

[shirleyb]

(d-40)(d+7)

ETA: Oh, never mind, that's not right. I think there's a typo on the problem. That's my answer and I'm sticking to it.

 

[Certifiable WDW Nut]

It's a quadratic equation, right?

Algebra was a long time ago.

 

[Lisa loves Pooh]

d is 20...

unfortunately I just plugged in numbers until I got it right.

20 (squared) - 20*33 + 280



oh wait--that didn't work.....crud! Are you sure it is MINUS 280???

 

[kdibattista]

I think it must be a misprint as well...

 

[Lisa loves Pooh]

aha

(d-40)(d+7)


figured it out by breaking down 280 into 2*2*2*5*7 and then played around with numbers...much the same way I did it in school.

 

[Lisa loves Pooh]

I think it must be a misprint as well...

I thought so--but I think she was stuck on minus and minus..but when you have a plus and a minus in the problem, you need a plus and a minus in the solution.....

ETA: OP--do you need d...or just the (d-40)(d+7) solution? If you need d---I can't remember how to get it.

 

[hiwaygal]

aha

(d-40)(d+7)


figured it out by breaking down 280 into 2*2*2*5*7 and then played around with numbers...much the same way I did it in school.

that works if the last symbol is - 280 not + 280.

I agree with the factors, just not the symbols a (neg) times a (pos) is a neg.

 

[Lisa loves Pooh]

that works if the last symbol is - 280 not + 280.

I agree with the factors, just not the symbols a (neg) times a (pos) is a neg.

oh crap--you are right...there has got to be a typo.

 

[Poohgirl]

I think its a typo as well. If you use the quadratic equation you come out with a square root of -31 in the formula, since 31 is a prime number and I don't think they would be going into complex conjugate numbers, it has to be wrong.

 

[korbbec]

http://www.akiti.ca/Quad2Deg.html

 

[bethbuchall]

I learned with my dd that sometimes "no solution" is valid answer. It looks as if that may be the case here.

Beth

 

[Katie]

I feel SOOOOOOOOOOOO much better now!

we had
(d-40)(d+7) but then a postive 280 would be wrong, it had to be -280!
I am glad to hear we weren't missing something really obvious!

 

[Ride Junkie]

I learned with my dd that sometimes "no solution" is valid answer. It looks as if that may be the case here.
Beth

I just took Algebra, and that would be my answer as well! No solution.

 

[princessmomma]

I just took Algebra, and that would be my answer as well! No solution.

Actually, there is "no real solution", if you are using the set of real numbers.

You could solve this using the set of imaginary numbers where "i" squared = -1. So the answer would be plus or minus "i square root 31".

(If square root of -31 is the answer using quadratic formula. I haven't figured it out, just used OP solution.)

 

[bethbuchall]

Actually, there is "no real solution", if you are using the set of real numbers.

You could solve this using the set of imaginary numbers where "i" squared = -1. So the answer would be plus or minus "i square root 31".

(If square root of -31 is the answer using quadratic formula. I haven't figured it out, just used OP solution.)

Yes, that is more accurate. I guess I was assuming that the poster's dd was still at a level that they wouldn't go beyond using real numbers.

 

[Simba's Mom]

I used to teach algebra, and I agree with everyone else. Either there's no solution or there's a typo and it was supposed to be -280. I tried the quadratic equation on it, and since it gave a negative number to take the square root of, the way it's written, it has to be no real solution.