Quick Homework Help

I am trying to factor trinomials:ax^2+bx+c.  There is nothing under solve that say anthing about trinomials. Explain, I don't know much about math. ⚑ Flag

by elease001 at March 17, 2011

Try -b+- SQR(b^2 - 4ac)/2a.  This will give you two values depending on whether you use the + sign or the - sign after the b.  This is called the quadratic formula.  It always works even if the answers are imaginary numbers!  You can test for that first by evaluating the numbers inside the parenthesis above.  If they end up being negative total, then your answers are imaginary numbers. Your should learn some common patterns like perfect squares and difference of two squares also.  A plus sign for c means the factors of c have the same sign.  If the b sign is positive, both c factors are positive.  If the b sign is negative, both c factors are negative.  If the c sign is negative, then the c factors have opposite signs.  Whatever the b factor sign is, the largest product of a factors and c factors will have that sign.    Hope that helps.  You may be asking for the calculator to solve your trinomial. If you have a TI-83 or TI-84, get the PolySim app.

kroo_jteague March 17, 2011

I forgot to say {-b+-SQR(b^2-4ac)} is all in the numerator.  I should have enclosed it as I have just done.

kroo_jteague March 17, 2011

What James said. MRREEEOOWWW.....

ChromeRedCat March 18, 2011

You can try solving with the quadratic formula which becomes really annoying. Use your calculator for that, but the formula is as follows (just write it out) x equals negative b, plus or minus the square root of b squared minus 4ac, all over 2a. (James has it written out down there)Also, it might be that you just didn't find the right values. Try drawing a big X. on the top, write what value you would get if you multiply a * c. On the bottom, write the b value. Then, try to find out what multiplies to the value on top but still adds up to the b value.Hope this somewhat helps

Gentou March 20, 2011