The 3rd one and the last one.
Answer:
x = 9
Step-by-step explanation:
2x - 9 = x
2x - x = 9
x = 9
For the first two, multiply 13 in place of the X. For example, 4(13)+71 = 123.
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:
85
Step-by-step explanation:
2x^3 + 3y^2 − 17
2(3)^3 + 3(4)^2 − 17
2*27 + 3*16 -17
54 + 48 -17 = 85