Question

Rezolvaţi în Z ecuațiile:
a) 3x - 9 = 0;
d) 3(x + 2) = 2(x - 1);
b) 3 = 4x – 13;
e) -7 + 4x = 1;
c) 3(x - 1) = 6;
f) (x + 3)(x - 2) = 0​

Answer 1

Explicație pas cu pas:

a) 3x = 9, x = 9:3 = 3

d) 3x+6 = 2x - 2

3x - 2x =-2-6

x = - 8

b) 4x = 3+13 = 16, x = 16:4 = 4

e) 4x = 1+7, 4x = 8, x = 8: 4 = 2

c) x-1 = 6: 3 = 2, x = 2+1 = 3

f) x+3 = 0, x = 0-2 = - 3

x-2 = 0, x = 0+2 = 2

Answer 2

Răspuns:

a) 3x-9=0 ⇒3x=9⇒x=3

d) 3(x+2)=2(x-1)⇒3x+6=2x-2⇒3x-2x=-2-6⇒x=-8

b) 3=4x-13⇒-4x=-13-3⇒4x=16⇒x=4

e) -7+4x=1⇒4x=8⇒x=2

c) 3(x-1)=6⇒3x-3=6⇒3x=9⇒x=3

f) (x+3)(x-2)=0⇒x²-2x+3x-6=0⇒x²+x-6=0

Δ=b²-4ac⇒1²-4×1×(-6)⇒Δ=25

x1,x2= -b±√Δ/2a ⇒x1,x2= -1±5/2⇒x1= -3 , x2= 2