If x=-1 and x=1 are the zeros of the polynomial ax^3+x^2-2x+b. Find the value of a and b.
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Hi friend,
Put x = -1 and x = 1 in given polynomial.
ax³+x²-2x+b
Put x = -1,
a(-1)³+(-1)²-2(-1)+b = 0
-a+1+2+b = 0
-a+b+3 = 0
-a+b = -3 -------(1)
Put x = 1,
a(1)³+(1)²-2(1)+b = 0
a+1-2+b = 0
a+b-1 = 0
a+b = 1 -------(2)
(2) + (1)
a + b = 1
-a + b = -3
--------------
2b = -2
b = -2/2 = -1
a+b = 1
a+(-1) = 1
a-1 = 1
a = 1+1
a = 2
Therefore, a = 2 and b = -1
Hope it helps....!!
Put x = -1 and x = 1 in given polynomial.
ax³+x²-2x+b
Put x = -1,
a(-1)³+(-1)²-2(-1)+b = 0
-a+1+2+b = 0
-a+b+3 = 0
-a+b = -3 -------(1)
Put x = 1,
a(1)³+(1)²-2(1)+b = 0
a+1-2+b = 0
a+b-1 = 0
a+b = 1 -------(2)
(2) + (1)
a + b = 1
-a + b = -3
--------------
2b = -2
b = -2/2 = -1
a+b = 1
a+(-1) = 1
a-1 = 1
a = 1+1
a = 2
Therefore, a = 2 and b = -1
Hope it helps....!!
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