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If x+1 and x-+2 are factors of the polynomial ax2+bx+c, ax^2 + bx + c,ax2+bx+c, a+b+c−a+b+c= ?\frac{a + b + c}{-a + b + c} = \, ? −a+b+ca+b+
Question

If x+1 and x-+2 are factors of the polynomial ax2+bx+c, ax^2 + bx + c, a+b+ca+b+c= ?\frac{a + b + c}{-a + b + c} = \, ? ​​

A.

72\frac{7}{2}

B.

-1

C.

1/2

D.

32\frac{3}{2}

Correct option is D

Given: 

The polynomial ax2+bx+cax^2 + bx + c , will be zero when x = -1 and x = -2 

Step 1: Substitute x = -1 in the polynomials: 

a(1)2+b(1)+c=0ab+c=0\\a(-1)^2 + b(-1) + c = 0 \\a - b + c = 0​​

Step 2: Substitute x = -2 in the polynomial: 

a(2)2+b(2)+c=04a2b+c=0(2)\\a(-2)^2 + b(-2) + c = 0 \\4a - 2b + c = 0 \quad \text{(2)}\\

Step 3: Subtract equation (1) from equation (2):  

(4a2b+c)(ab+c)=04a2b+ca+bc=03ab=0b=3a\\(4a - 2b + c) - (a - b + c) = 0 \\4a - 2b + c - a + b - c = 0 \\3a - b = 0 \\b = 3a\\​​

Step 4: Substitute b = 3a into equation (1): 

a - 3a + c = 0 

-2a + c = 0 

c = 2a 

Step 5: Substitute b = 3a and c = 2a into a+b+ca+b+c:\frac{a + b + c}{-a + b + c}:

a+b+c=a+3a+2a=6aa+b+c=a+3a+2a=4a\\a + b + c = a + 3a + 2a = 6a \\-a + b + c = -a + 3a + 2a = 4a \\

Step6:Simplifytheratio:a+b+ca+b+c=6a4a=32{Step 6: Simplify the ratio: } \\\frac{a + b + c}{-a + b + c} = \frac{6a}{4a} = \frac{3}{2}\\​​

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