Question

x+3[3x+2(y-2)]=-8
3x-2[4y+5(x-3)]=31

Answer 1

Răspuns:

x=1

y=-1

Explicație pas cu pas:

X+3[3x+2(y-2)]=-8  ⇒x+9x+6(y-2)=-8  ⇒10x+6y=-8+12           ⇒10x+6y=4

3x-2[4y+5(x-3)]=31  ⇒3x-8y-10(x-3)=31  ⇒3x-8y-10x+30=31  ⇒-7x-8y=1  ⇒

10x+6y=4 I:2  ⇒5x+3y=2

-7x-8y=1  ⇒       -7x-8y=1  ⇒-7x=1+8y  ⇒x=-(1+8y)/7  inlocuim pe x in relatia 5x+3y=2   ⇒5·-(1+8y)/7+3y=2  ⇒(-5-40y+21y)/7=2  ⇒-5-19y=14  ⇒-19y=19  ⇒y=-1  ⇒

x=-(1+8y)/7  ⇒x=-(1-8)/7 = -(-7)/7=1  x=1