va rog, dau coroana!

Răspuns:
1. 2x+5=13 => 2x=13-5=> x=8:2=>x=4
2. 2x+5=15=>2x=15-5=>x=10:2=>x=5
3x-5=13=>3x=13+5=>x=18:3=6
5 ≠ 6
nu sunt echivalente ecuatiile
3. 3x²-147=0
3(x²-49)=0
x²=±49
x=±7
4.2m×(-1)+5=11
-2m=11-5
m=-6/2=>m=-3