Question

If the sum of the coefficients in the expansion of (x-2y+3z)^n is 128

Answer 1

Question:

If the sum of the coefficients in the expansion of (x - 2y + 3z)ⁿ is 128, then find the value of n.

Answer:

n = 7

Step-by-step explanation:

For such problems, consider only the coefficients of the terms and the exponent and the sum, means let away the x, y and z!!!

Given is (x - 2y + 3z)ⁿ, where the coefficients of x, y and z are 1, -2 and 3 respectively. And given that the sum of coefficients in the expansion of it is 128.

By letting away those x, y and z, and by considering only the coefficients and the exponent, and the sum, we get,

⇒ (1 - 2 + 3)ⁿ = 128

⇒ 2ⁿ = 128

⇒ 2ⁿ = 2⁷

∴ n = 7