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drawback drawback Dec 10, 2020

If x³-3x²+3x+7=(x+1) (ax²+bx+c) then find the value of a+b+c​

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Answer:

Step-by-step explanation:If x³ - 3x² + 3x - 7 = (x + 1)(ax² + bx + c), then find (a + b + c)

first multiply

(x + 1)(ax² + bx + c)

= ax³ + bx² + cx + ax² + bx + c

= ax³ + bx² + ax² + cx + bx + c

= ax³ + (b+a)x² + (c + b)x + c

comparing it with

x³ - 3x² + 3x - 7

a = 1

b + a = -3 => b + 1 = -3 => b = -4

c + b = 3 = > c - 4 = 3 => c = 7

c = -7 should be 7

as if we put x = -1 in

x³ - 3x² + 3x - 7

-1 - 3 - 3 - 7 = 14 so x + 1 can not be factor so x +1 will be factor if

x³ - 3x² + 3x - 7 is actually

x³ - 3x² + 3x + 7

then -1 - 3 - 3 + 7 = 0

hence we can say that

a = 1

b = -4

c = 7

so a + b + c = 4

446
Pekka Pekka
Dec 10, 2020
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