Question

resolva as equações em seu caderno. A- 3x+15x=0 B- 2y-y/3=0 C- 9.(2n-5).(n+2)=0 D- 2x-3/x-3=3x-1/x-2(x#6 e x#2)

Answer 1

A)3 X + 15 X = 0
18 X = 0
X = 0/18
X = 0
B)-2 Y - Y/3 = 0
m.m.c = 3
-6 y/3 - y/3 = 0
-7 y/3 = 0
-7 y = 3 . 0
-7 y = 0
y = 0/-7
y = 0
C)9(2 n- 5 )(n + 2 ) =
    9 (2 n² + 4 n - 5 n - 10)=
   9 (2 n² - 1 n - 10 ) = 0
18 n² - 9 n - 90 = 0
Δ = b² - 4.a.c
Δ = (-9)² - 4.18.-90
Δ = 81 + 6480
Δ = 6561 ⇒√6461 = 81
n´= -b + ou - 81/2.18
n´= -(-9) + 81/36
n´= 9 + 81/36
n´= 90/36 = 2,5
n´´ = 9 - 81/36
n´´ = -72/36⇒-2
D)2 X - 3 / X- 3 = 3 X - 1 / X - 23 X² - X - 9 X + 3 = 2 X² - 4 X - 3 X + 6
3 X² - 2 X² - 10 X + 3 = -7 X + 6
X²  - 10 X + 7 X = 6 - 3
X² - 3 X = 3
X² - 3 X - 3 = 0
Δ = B² - 4.A.C
Δ= (-3)² - 4.1.-3
Δ = 9 + 12
Δ = 21 = √21
x = - b + ou -√21/2.1
x´= -(-3) + √21/2
x´= 3 + √21/2
x´´ = 3 - √21/12