Question

b la puterea 2 +(b+1) la puterea2 = 841 b este egal cu

Answer 1

b²+(b+1)² = 841

b² + b² + 2b +1 - 841 = 0

2b² +2b -840= 0 /:2

b² + b - 420= 0

Δ= b²-4ac = 1+1680 = 1681

b1 = (-b+√Δ)/2a = (-1+41)/2 = 40/2 = 20

b2 = (-b-√Δ)/2a = (-1-41)/2= -42/2 = -21

S={-21, 20}