Answer:
x = 9 + 6i or x = 9 - 6i
Step-by-step explanation:
x² - 18x + 117 = 0
Complete the square and solve:
(x - 9)² - 81 + 117 = 0
(x - 9)² + 36 = 0
(x - 9)² = -36
x - 9 = ±sqrt(-36)
x - 9 = ±sqrt(-1).sqrt(36)
i = imaginary number = sqrt(-1)
x - 9 = ±6i
x = 9 ± 6i
There are no real solutions, only imaginary ones
9 + 6i and 9 - 6i
Answer:
x = 12
Step-by-step explanation:
In similarity triangles angles are congruent.
∠D = ∠A
x² - 8x = 48
x² - 8x - 48 = 0
x² + 4x - 12x - 48 = 0
x(x + 4) - 12(x + 4) = 0
(x +4)(x - 12) = 0
x - 12 = 0 {Ignore x + 4 = 0, as measurements won't have negative values}
x = 12
Are you sure you want ONLY the coefficient of b? If you expand this, you will have b in 3 of 4 terms.
According to Pascal's Triangle, the coefficients of (a+b)^4 are as follows:
1
1 2 1
1 3 3 1
1 4 6 4 1
So (a+b)^4 would be 1a^4 + 4a^3b + 6a^2b^2 + 4ab^3 + b^4
Here, you want (3 + b)^4. Here's what that looks like:
3^4 + 4[3^3*b] + 6[3^2*b^2] + 4[3*b^3] + 1[b^4]
Which coeff did you want?
