Fill in the blanks

If x = -9 is a root of , then other two roots are ___.


If x = -9 is a root of , then other two roots are 2 and 7.

Explanation:


Given x = -9 is a root of .



x [x2 – 12] – 3 [2x – 14] + 7 [12 – 7x] = 0


x3 – 12x – 6x + 42 + 84 – 49x = 0


x3 – 67x + 126 =0


Here, 126 × 1 = 9 × 2 × 7


For x = 2,


23 – 67 (2) + 126 = 134 – 134 = 0


x = 2 is one root.


For x = 7,


73 – 67 (7) + 126 = 469 – 469 = 0


x = 7 is also one root.


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