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log-5-3-x-x-2-2-log-5-x-2-7x-12-log-5-5-x-




Question Number 89451 by jagoll last updated on 17/Apr/20
log_5  ((3−x)(x^2 +2)) ≥ log_5 (x^2 −7x+12)+log_5 (5−x)
log5((3x)(x2+2))log5(x27x+12)+log5(5x)
Answered by john santu last updated on 17/Apr/20
(1) (3−x)(x^2 +2) > 0   ⇒ x < 3   (2) x^2 −7x+12 > 0  (x−3)(x−4) > 0   ⇒x < 3 ∨ x > 4  (3) 5 −x > 0 ⇒ x < 5  (4) (3−x)(x^2 +2) ≥ (x−3)(x−4)(5−x)   ⇒(3−x)(x^2 +2)+(3−x)(x−4)(5−x)≥0  (3−x) {x^2 +2−x^2 +9x−20} ≥ 0  (3−x)(9x−18)≥ 0  ⇒ 2 ≤ x ≤ 3  solution : 2 ≤ x < 3
(1)(3x)(x2+2)>0x<3(2)x27x+12>0(x3)(x4)>0x<3x>4(3)5x>0x<5(4)(3x)(x2+2)(x3)(x4)(5x)(3x)(x2+2)+(3x)(x4)(5x)0(3x){x2+2x2+9x20}0(3x)(9x18)02x3solution:2x<3
Commented by jagoll last updated on 17/Apr/20
thank you
thankyou

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