these are the questions .... please ull be helping a little struggling boy
when a postive number is added to its square, the total is 12.find that number?
2007-03-23 02:25:51 · 13 answers · asked by barcaroni2009 1 in Science & Mathematics ➔ Mathematics
x + x^2 = 12
x^2 + x - 12 = 0
(x + 4)(x - 3) = 0
x = 3, and -4
Since we know it's a "positive number" from the question, the answer is 3.
2007-03-23 02:28:50 · answer #1 · answered by Mathematica 7 · 1⤊ 0⤋
The sentence that you just stated is an equation; write it down just like you read it. The positive number is N; now add it to its square N + N^2. Then N + N^2 = 12. Now solve the equation N^2 + N -12 = 0. Factor the equation to
(N+4) (N-3) = 0. Solving N+4 = 0 or N-3=0 or N=-4 or N=3. Since it has to be a positive number, the answer is 3 even though the -4 will also solve the equation.
2007-03-23 02:48:15 · answer #2 · answered by Doug R 5 · 0⤊ 0⤋
3
2007-03-23 02:32:37 · answer #3 · answered by shilpu 2 · 0⤊ 0⤋
Yes, a little struggling boy indeed you must be, but the solution is quite simple, using that branch of Maths called Algebra. Ever heard of that name? Well, here we go:
Let the number you are looking for be represented by the letter x; according to the description of your problem, the following expression holds:
x * x + x = 12 ( true or false?)
or x^2 + x - 12 = 0
Factorize this equation to get (x + 4)(x - 3) = 0
This gives a solution of x = 3 or -4.
Since you are looking for a positive number, your answer will be the number 3
2007-03-23 02:39:40 · answer #4 · answered by Paleologus 3 · 0⤊ 0⤋
x+x^2 = 12
x^2+x-12 = 0
Using the quadratic formula:
(-1 (+or -)sqrt(1+48))/(2)
You get 2 results:
One is 3 and the other is -4. However the question asked for the positive number so x=3
2007-03-23 02:32:31 · answer #5 · answered by Tenebra98 3 · 0⤊ 0⤋
This is the same as saying:
x^2 + x = 12. Solve for x.
x^2 + x -12 = 0
(x+4)(x-3) = 0
So x must be -4 or 3. Since you said it's positive, it must be 3.
2007-03-23 02:37:11 · answer #6 · answered by Anonymous · 0⤊ 0⤋
Just solve for the x and you will have your answer good luck.
x+x2=12
3+9=12
x^2+x-12=0
(x+4)(x-3)=0
X=3 and -4
so since we know it's a positive number from the question so x is going to be 3 since you said it's positive and now you have your answer that's all you have to do when it positive good luck .
2007-03-23 02:36:16 · answer #7 · answered by lil boosie 4 · 0⤊ 0⤋
One way to look at is: what numbers do you know that are square and less than 12
1,4,9
The numbers before squaring are 1,2,3
It is possible to see that 3 plus it's square (9) is 12.
2007-03-23 02:38:33 · answer #8 · answered by peateargryfin 5 · 0⤊ 0⤋
3
x + x2 = 12
3 + 9 = 12
2007-03-23 02:34:58 · answer #9 · answered by identity_letters 2 · 0⤊ 0⤋
the no. is X
then: X+X^2= 12
X^2+X-12=0
(X+4)(X-3)=0
X=-4 , X=3
we want the positive......... X=3
2007-03-23 02:32:30 · answer #10 · answered by JwH 2 · 0⤊ 0⤋