Question 623409


{{{252v^2+588vg+343g^2}}} Start with the given expression.



{{{7(36v^2+84gv+49g^2)}}} Factor out the GCF {{{7}}}.



Now let's try to factor the inner expression {{{36v^2+84gv+49g^2}}}



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Looking at the expression {{{36v^2+84gv+49g^2}}}, we can see that the first coefficient is {{{36}}}, the second coefficient is {{{84}}}, and the last coefficient is {{{49}}}.



Now multiply the first coefficient {{{36}}} by the last coefficient {{{49}}} to get {{{(36)(49)=1764}}}.



Now the question is: what two whole numbers multiply to {{{1764}}} (the previous product) <font size=4><b>and</b></font> add to the second coefficient {{{84}}}?



To find these two numbers, we need to list <font size=4><b>all</b></font> of the factors of {{{1764}}} (the previous product).



Factors of {{{1764}}}:

1,2,3,4,6,7,9,12,14,18,21,28,36,42,49,63,84,98,126,147,196,252,294,441,588,882,1764

-1,-2,-3,-4,-6,-7,-9,-12,-14,-18,-21,-28,-36,-42,-49,-63,-84,-98,-126,-147,-196,-252,-294,-441,-588,-882,-1764



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



These factors pair up and multiply to {{{1764}}}.

1*1764 = 1764
2*882 = 1764
3*588 = 1764
4*441 = 1764
6*294 = 1764
7*252 = 1764
9*196 = 1764
12*147 = 1764
14*126 = 1764
18*98 = 1764
21*84 = 1764
28*63 = 1764
36*49 = 1764
42*42 = 1764
(-1)*(-1764) = 1764
(-2)*(-882) = 1764
(-3)*(-588) = 1764
(-4)*(-441) = 1764
(-6)*(-294) = 1764
(-7)*(-252) = 1764
(-9)*(-196) = 1764
(-12)*(-147) = 1764
(-14)*(-126) = 1764
(-18)*(-98) = 1764
(-21)*(-84) = 1764
(-28)*(-63) = 1764
(-36)*(-49) = 1764
(-42)*(-42) = 1764


Now let's add up each pair of factors to see if one pair adds to the middle coefficient {{{84}}}:



<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>1764</font></td><td  align="center"><font color=black>1+1764=1765</font></td></tr><tr><td  align="center"><font color=black>2</font></td><td  align="center"><font color=black>882</font></td><td  align="center"><font color=black>2+882=884</font></td></tr><tr><td  align="center"><font color=black>3</font></td><td  align="center"><font color=black>588</font></td><td  align="center"><font color=black>3+588=591</font></td></tr><tr><td  align="center"><font color=black>4</font></td><td  align="center"><font color=black>441</font></td><td  align="center"><font color=black>4+441=445</font></td></tr><tr><td  align="center"><font color=black>6</font></td><td  align="center"><font color=black>294</font></td><td  align="center"><font color=black>6+294=300</font></td></tr><tr><td  align="center"><font color=black>7</font></td><td  align="center"><font color=black>252</font></td><td  align="center"><font color=black>7+252=259</font></td></tr><tr><td  align="center"><font color=black>9</font></td><td  align="center"><font color=black>196</font></td><td  align="center"><font color=black>9+196=205</font></td></tr><tr><td  align="center"><font color=black>12</font></td><td  align="center"><font color=black>147</font></td><td  align="center"><font color=black>12+147=159</font></td></tr><tr><td  align="center"><font color=black>14</font></td><td  align="center"><font color=black>126</font></td><td  align="center"><font color=black>14+126=140</font></td></tr><tr><td  align="center"><font color=black>18</font></td><td  align="center"><font color=black>98</font></td><td  align="center"><font color=black>18+98=116</font></td></tr><tr><td  align="center"><font color=black>21</font></td><td  align="center"><font color=black>84</font></td><td  align="center"><font color=black>21+84=105</font></td></tr><tr><td  align="center"><font color=black>28</font></td><td  align="center"><font color=black>63</font></td><td  align="center"><font color=black>28+63=91</font></td></tr><tr><td  align="center"><font color=black>36</font></td><td  align="center"><font color=black>49</font></td><td  align="center"><font color=black>36+49=85</font></td></tr><tr><td  align="center"><font color=red>42</font></td><td  align="center"><font color=red>42</font></td><td  align="center"><font color=red>42+42=84</font></td></tr><tr><td  align="center"><font color=black>-1</font></td><td  align="center"><font color=black>-1764</font></td><td  align="center"><font color=black>-1+(-1764)=-1765</font></td></tr><tr><td  align="center"><font color=black>-2</font></td><td  align="center"><font color=black>-882</font></td><td  align="center"><font color=black>-2+(-882)=-884</font></td></tr><tr><td  align="center"><font color=black>-3</font></td><td  align="center"><font color=black>-588</font></td><td  align="center"><font color=black>-3+(-588)=-591</font></td></tr><tr><td  align="center"><font color=black>-4</font></td><td  align="center"><font color=black>-441</font></td><td  align="center"><font color=black>-4+(-441)=-445</font></td></tr><tr><td  align="center"><font color=black>-6</font></td><td  align="center"><font color=black>-294</font></td><td  align="center"><font color=black>-6+(-294)=-300</font></td></tr><tr><td  align="center"><font color=black>-7</font></td><td  align="center"><font color=black>-252</font></td><td  align="center"><font color=black>-7+(-252)=-259</font></td></tr><tr><td  align="center"><font color=black>-9</font></td><td  align="center"><font color=black>-196</font></td><td  align="center"><font color=black>-9+(-196)=-205</font></td></tr><tr><td  align="center"><font color=black>-12</font></td><td  align="center"><font color=black>-147</font></td><td  align="center"><font color=black>-12+(-147)=-159</font></td></tr><tr><td  align="center"><font color=black>-14</font></td><td  align="center"><font color=black>-126</font></td><td  align="center"><font color=black>-14+(-126)=-140</font></td></tr><tr><td  align="center"><font color=black>-18</font></td><td  align="center"><font color=black>-98</font></td><td  align="center"><font color=black>-18+(-98)=-116</font></td></tr><tr><td  align="center"><font color=black>-21</font></td><td  align="center"><font color=black>-84</font></td><td  align="center"><font color=black>-21+(-84)=-105</font></td></tr><tr><td  align="center"><font color=black>-28</font></td><td  align="center"><font color=black>-63</font></td><td  align="center"><font color=black>-28+(-63)=-91</font></td></tr><tr><td  align="center"><font color=black>-36</font></td><td  align="center"><font color=black>-49</font></td><td  align="center"><font color=black>-36+(-49)=-85</font></td></tr><tr><td  align="center"><font color=black>-42</font></td><td  align="center"><font color=black>-42</font></td><td  align="center"><font color=black>-42+(-42)=-84</font></td></tr></table>



From the table, we can see that the two numbers {{{42}}} and {{{42}}} add to {{{84}}} (the middle coefficient).



So the two numbers {{{42}}} and {{{42}}} both multiply to {{{1764}}} <font size=4><b>and</b></font> add to {{{84}}}



Now replace the middle term {{{84gv}}} with {{{42gv+42gv}}}. Remember, {{{42}}} and {{{42}}} add to {{{84}}}. So this shows us that {{{42gv+42gv=84gv}}}.



{{{36v^2+highlight(42gv+42gv)+49g^2}}} Replace the second term {{{84gv}}} with {{{42gv+42gv}}}.



{{{(36v^2+42gv)+(42gv+49g^2)}}} Group the terms into two pairs.



{{{6v(6v+7g)+(42gv+49g^2)}}} Factor out the GCF {{{6v}}} from the first group.



{{{6v(6v+7g)+7g(6v+7g)}}} Factor out {{{7g}}} 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.



{{{(6v+7g)(6v+7g)}}} Combine like terms. Or factor out the common term {{{6v+7g}}}



{{{(6v+7g)^2}}} Condense the terms.



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So {{{7(36v^2+84gv+49g^2)}}} then factors further to {{{7(6v+7g)^2}}}



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Answer:



So {{{252v^2+588vg+343g^2}}} completely factors to {{{7(6v+7g)^2}}}.



In other words, {{{252v^2+588vg+343g^2=7(6v+7g)^2}}}.



Note: you can check the answer by expanding {{{7(6v+7g)^2}}} to get {{{252v^2+588vg+343g^2}}} or by graphing the original expression and the answer (the two graphs should be identical).