A polynomial “ax3 + bx2 + cx + d” intersects x-axis at 1 and –1, and y-axis at 2. The value of b is:
Explanation:
ax3 + bx2 + cx + d intersects x axis at 1 & –1
∴ a + b + c + d = 0
–a + b – c + d = 0
∴ 2(b + d) = 0
∴ b + d = 0
ax3 + bx2 + cx + d intersects y axis at 2
0 + d = 2
∴ d = 2
From (1) & (2), b = –2
Hence, option (a).
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