Question 658085


Looking at the expression {{{m^2+2m-24}}}, we can see that the first coefficient is {{{1}}}, the second coefficient is {{{2}}}, and the last term is {{{-24}}}.



Now multiply the first coefficient {{{1}}} by the last term {{{-24}}} to get {{{(1)(-24)=-24}}}.



Now the question is: what two whole numbers multiply to {{{-24}}} (the previous product) <font size=4><b>and</b></font> add to the second coefficient {{{2}}}?



To find these two numbers, we need to list <font size=4><b>all</b></font> of the factors of {{{-24}}} (the previous product).



Factors of {{{-24}}}:

1,2,3,4,6,8,12,24

-1,-2,-3,-4,-6,-8,-12,-24



Note: list the negative of each factor. This will allow us to find all possible combinations.



These factors pair up and multiply to {{{-24}}}.

1*(-24) = -24
2*(-12) = -24
3*(-8) = -24
4*(-6) = -24
(-1)*(24) = -24
(-2)*(12) = -24
(-3)*(8) = -24
(-4)*(6) = -24


Now let's add up each pair of factors to see if one pair adds to the middle coefficient {{{2}}}:



<table border="1"><th>First Number</th><th>Second Number</th><th>Sum</th><tr><td  align="center"><font color=black>1</font></td><td  align="center"><font color=black>-24</font></td><td  align="center"><font color=black>1+(-24)=-23</font></td></tr><tr><td  align="center"><font color=black>2</font></td><td  align="center"><font color=black>-12</font></td><td  align="center"><font color=black>2+(-12)=-10</font></td></tr><tr><td  align="center"><font color=black>3</font></td><td  align="center"><font color=black>-8</font></td><td  align="center"><font color=black>3+(-8)=-5</font></td></tr><tr><td  align="center"><font color=black>4</font></td><td  align="center"><font color=black>-6</font></td><td  align="center"><font color=black>4+(-6)=-2</font></td></tr><tr><td  align="center"><font color=black>-1</font></td><td  align="center"><font color=black>24</font></td><td  align="center"><font color=black>-1+24=23</font></td></tr><tr><td  align="center"><font color=black>-2</font></td><td  align="center"><font color=black>12</font></td><td  align="center"><font color=black>-2+12=10</font></td></tr><tr><td  align="center"><font color=black>-3</font></td><td  align="center"><font color=black>8</font></td><td  align="center"><font color=black>-3+8=5</font></td></tr><tr><td  align="center"><font color=red>-4</font></td><td  align="center"><font color=red>6</font></td><td  align="center"><font color=red>-4+6=2</font></td></tr></table>



From the table, we can see that the two numbers {{{-4}}} and {{{6}}} add to {{{2}}} (the middle coefficient).



So the two numbers {{{-4}}} and {{{6}}} both multiply to {{{-24}}} <font size=4><b>and</b></font> add to {{{2}}}



Now replace the middle term {{{2m}}} with {{{-4m+6m}}}. Remember, {{{-4}}} and {{{6}}} add to {{{2}}}. So this shows us that {{{-4m+6m=2m}}}.



{{{m^2+highlight(-4m+6m)-24}}} Replace the second term {{{2m}}} with {{{-4m+6m}}}.



{{{(m^2-4m)+(6m-24)}}} Group the terms into two pairs.



{{{m(m-4)+(6m-24)}}} Factor out the GCF {{{m}}} from the first group.



{{{m(m-4)+6(m-4)}}} Factor out {{{6}}} from the second group. The goal of this step is to make the terms in the second parenthesis equal to the terms in the first parenthesis.



{{{(m+6)(m-4)}}} Combine like terms. Or factor out the common term {{{m-4}}}



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Answer:



So {{{m^2+2m-24}}} factors to {{{(m+6)(m-4)}}}.



In other words, {{{m^2+2m-24=(m+6)(m-4)}}}.



Note: you can check the answer by expanding {{{(m+6)(m-4)}}} to get {{{m^2+2m-24}}} or by graphing the original expression and the answer (the two graphs should be identical).