Page 156 - aljaber

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. x

300 .x − 40

x + (x − 40) ≤ 300 ⇔ 2x ≤ 340

⇔ x ≤ 170

. 170

12.7 ( ) x ()

x

. x < 10 2.5 < x + 1 .12.65 ≤ x < 12.75
x ()

x < 10 2.5 < x + 1 ⇔ x < 15.8 < x + 1
⇔ 14.8 < x < 15.8

. x = 15

6.5 ≤ y ≤ 9.5 5 ≤ x ≤ 7 ( )

x
y