Question

If a,b,1 are roots of x^3-2x^2-5x+6=0(a is greater than 1) then 3a + B =​

Answer 1

Step-by-step explanation:

a + b + 1 = 2

a + b = 1 ------(1)

ab + b + a = -5

ab + 1 = -5

ab = -6 -----(2)

Now , a - b = √(a + b)² - 4ab

= √(1)² - 4(-6)

= √1 + 24

= √25

a - b = 5 ------(3)

from equation (1) + (3)

2a = 6

a = 3

then b = 1 - 3 = -2

Therefore , 3a + b

= 3(3) + (-2)

= 9 - 2 = 7