ok im basically stuck in al laspects of algebra because i dont no how to factor. if i no what form it is and i no the steps involed i cna do it. obviously , but sometimes the forms i cant tell the difference. for instance. 5x^2+5x-30= 5(x-2)(x+3) according to the book. isnt this equation in the quadratic formula form. and that form states u multiple a x c and that answer adds to get b. IE 5 x 30 = 120 and add to get 5. but isnce the answer is -2, 3 . i dont get it. can someone please help me understand this.
2007-10-31 17:20:54 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
the formula is
b plus or minus the square root of b squared - 4 times a times c over 2 times a
the book is correct. Since you can factor out a number that is able to go into each of the numbers
use the formula only if you can not factor the equation
2007-10-31 17:24:18 · answer #1 · answered by Ms. Exxclusive 5 · 0⤊ 0⤋
Somewhere you got bad advice.
When you factor out the 5, you have x^2+x-6.
Having an equation with 1 for the coefficient of the x^2 term makes life much easier. To find factors, you look for 2 numbers whose sum is +1 and whose product is -6. The numbers are +3 and -2.
2007-11-01 00:39:05 · answer #2 · answered by cattbarf 7 · 0⤊ 0⤋
Before you factorise the expression always divide the whole expression with the biggest common factor. In this case the biggest common factor is 5.
Dividing the expression with 5 leaves
x^2 +x - 6 which is factorised into (x+3)(x-2)
For how to factorise a general expression go to the link below for a detail explanation.
http://answers.yahoo.com/question/index;_ylt=AiwwmtZ7pcKTgRtRq2hq6DoCxgt.;_ylv=3?qid=20071031201033AA9Jyet
2007-11-01 00:50:58 · answer #3 · answered by SL 2 · 0⤊ 0⤋