Page 129 - aljaber

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x = 8± 64 − 4(1)(−1280) = 8 ± 5184 = 8 ± 72 ()
2 22
.y
. x = 8 + 72 = 40

2

. x − 8 = 32
x :( )

x + y = 10

xy = 30

.y = 10 − x

x(10 − x) = 30
10x − x2 = 30
x 2 − 10x + 30 = 0
∆ = b2 − 4ac = 100 − 120 = −20

..

.x :( ) ()

.x + 2

x(x + 2) = 360
x2 + 2x − 360 = 0
(x + 20)(x − 18) = 0

x = −20 x = 18

. x + 2 = 20 .x = 18 x

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