Question

The polynomial f (x) =x3 + 15x2 +9x-a a when divided by (x-4) leaves a reminder 80, find the vlue of a

Answer 1

Heya !


First you have to divide the polynomial and then you will get the remainder and then you have to find the value of a

Answer 2

HOLA!!!

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HERE YOUR SOLUTION IS

x-4= 0

x = 4

Now substitute x = 4 in f (x)

f (x) = x^3 + 15x^2 + 9x - a

f ( 4) = (4)^3 +15 (4)^4 +9 (4)-a

80 = 64 + 15 (16)+36 -a


80 = 64 + 240 + 36 -a

80 = 340 - a

a = 340 - 80

a = 260

Therefore value of a = 260

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in third step I used 80 instead of f (4) because we used x= 4 to obtain remainder 80. So it can be used.

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HOPE IT HELPS YOU :D