Page 191 - aljaber

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.

mα

. m =1 .m

r1 [AHSME 1965] ( )
r2
y +1 y −1 f (y) = y2 + my + 2

.m r1 = r2

r1 = f (1) = 12 + m × 1 + 2 = m + 3

r2 = f (−1) = (−1)2 + m ×(−1) + 2 = −m + 3

2m = 0 .m + 3 = −m + 3 r1 = r2

.m = 0

. f (x) = x 3 + 5x2 + 2x − 8 ()

.{±1,±2, ±4,±8} 8

f (1) = 13 + 5 × 12 + 2 × 1 − 8 = 0 −4
f (−2) = −8 + 20 − 4 − 8 = 0
f (−4) = −64 + 80 − 8 − 8 = 0 .(

) 1 −2