Well first off there is no other factors of 7 otherwise "7,1" so we can assume the answer would look something along the lines of (... 1)(... 7)
Next we find out (By trail and error) the factors of nine that add up to 18, which is 9,1 and 3,3, however the only factor that is possible for this problem would be 3,3.
Now we know the equation would look something like (3x 1)(3x 7).
If you think about the signs, you should know that 3 times 7 is 21, and if subtracted by 3, would give us the magical 18 that we need to prove out answer is correct.
After messing with the equation with the positive and negative possibilities...
You are left with (3x+1)(-3x+7) ; which if simplified out you will get the original equation so it all checks out to be correct. ^_^
~Hope this helps~
Next we find out (By trail and error) the factors of nine that add up to 18, which is 9,1 and 3,3, however the only factor that is possible for this problem would be 3,3.
Now we know the equation would look something like (3x 1)(3x 7).
If you think about the signs, you should know that 3 times 7 is 21, and if subtracted by 3, would give us the magical 18 that we need to prove out answer is correct.
After messing with the equation with the positive and negative possibilities...
You are left with (3x+1)(-3x+7) ; which if simplified out you will get the original equation so it all checks out to be correct. ^_^
~Hope this helps~