Answer:
The first one is missing (d - 9) so it would be 5(d -9) or when you factor it out 5d - 45
In the second one (d + 7) is missing so it will be 8d(d + 7) so if you factor that out you will receive 8d^2 + 56
Step-by-step explanation:
3d^2 + 18d -21 =(3d -3)( d + 7)
3d^2 -30d +27 =(3d -3)(d - 9)
Step-by-step explanation:
![\left[\begin{array}{ccc}2&6&3\\-5&1&4\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D2%266%263%5C%5C-5%261%264%5Cend%7Barray%7D%5Cright%5D)
R1 ÷ 2 = ![\left[\begin{array}{ccc}1&3&1.5\\-5&1&4\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%263%261.5%5C%5C-5%261%264%5Cend%7Barray%7D%5Cright%5D)
R2 ÷ -5 = ![\left[\begin{array}{ccc}1&3&1.5\\1&-0.2&-0.8\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%263%261.5%5C%5C1%26-0.2%26-0.8%5Cend%7Barray%7D%5Cright%5D)
R2: R1 - R2 = ![\left[\begin{array}{ccc}1&3&1.5\\0&3.2&2.3\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%263%261.5%5C%5C0%263.2%262.3%5Cend%7Barray%7D%5Cright%5D)
R2 ÷ 3.2 = ![\left[\begin{array}{ccc}1&3&1.5\\0&1&0.71875\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%263%261.5%5C%5C0%261%260.71875%5Cend%7Barray%7D%5Cright%5D)
R1: R1 - 3R2 = ![\left[\begin{array}{ccc}1&0&0.65625\\0&1&0.71875\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%260%260.65625%5C%5C0%261%260.71875%5Cend%7Barray%7D%5Cright%5D)
Answer: x = 0.65625, y = 0.71875
So you would distribute what's in the parenthesis and end up with 4x-2x-6=x+1, then you combine like terms and end up with 2x-6=x+1, now you can add 6 to both sides or subtract 1 both sides (basically anything goes for this step just make sure you apply the same thing on both sides) so I'll add 6 and continue just to show you... then you end up with 2x=x+7 then you subtract 1x on both sides to get x=7. sorry it's a lot hopefully you get it know!
