If the expression (lx2 + mx + n) is equal to -4 when x = 0, it leaves reminder 5, when divided by (x - 3) and a reminder 3, when divided by (x + 1), then find the value of (l + m + n).
If the expression (lx2 + mx + n) is equal to -4 when x = 0, it leaves reminder 5, when divided by (x - 3) and a reminder 3, when divided by (x + 1), then find the value of (l + m + n). Correct Answer -6
lx2 + mx + n = -4 at x = 0
Putting x = 0:
⇒ n = -4
The expression leaves reminder 5 when divided by (x - 3);
∴ Putting x = 3 in the expression:
⇒ 9l + 3m - 4 = 5
⇒ 9l + 3m = 9
⇒ 3l + m = 3 ----(1)
The expression leaves reminder 3 when divided by (x + 1);
∴ Putting x = -1 in the expression:
⇒ l - m - 4 = 3
⇒ l - m = 7 ----(2)
From equation (1) and (2)
l = 10/4, m = -18/4 and n = -4
∴ (l + m + n) = 10/4 - 18/4 - 4 = -6
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Feb 20, 2025