In order to factor , first we need to ask ourselves: What two numbers multiply to -3 and add to -2? Lets find out by listing all of the possible factors of -3
Factors:
1,3,
-1,-3,List the negative factors as well. This will allow us to find all possible combinations
These factors pair up to multiply to -3.
(-1)*(3)=-3
Now which of these pairs add to -2? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to -2
| First Number | | | Second Number | | | Sum | | 1 | | | -3 | || | 1+(-3)=-2 | | -1 | | | 3 | || | (-1)+3=2 | We can see from the table that 1 and -3 add to -2.So the two numbers that multiply to -3 and add to -2 are: 1 and -3
Now we substitute these numbers into a and b of the general equation of a product of linear factors which is:
substitute a=1 and b=-3
So the equation becomes:
(x+1)(x-3)
Notice that if we foil (x+1)(x-3) we get the quadratic again
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