Question

A,B are roots of y^2-2y-7=0 find a) a^2+B^2 b) a^3+B^3​

Answer 1

Answer:

a) 18 b) 50

Step-by-step explanation:

given equation is:- y^2-2y-7=0.

compare this with standard form which is ax^2+bx+c=0.

we get, a=1, b= -2, c= -7.

Then, (A+B) = -b/a = -(-2)/1 = 2.

AB = c/a = -7/1 =-7.

a) A^2+B^2 = (A+B)^2- 2AB = 2^2-2× (-7) = 4+14 = 18. .....(I)

b) A^3+B^3 = (A+B) (A^2- AB + B^2) = 2×{18-(-7)} =2×25 = 50.

Hope it helps you.