Question

tesolva: 4(×+5)+3(×+5)=21 13+4(2×-1)-5(×+2)=0

Answer 1

4(×+5)+3(×+5)=21
4x+20+3x+15=21
7x+35=21
7x+35-21=0
7x+14=0
7x=14
x=14/7 
x=2
 a outra
13+4(2×-1)-5(×+2)=0
17(2x-1)- 5x+10=0
34x-17-5x+10=0
29x-7=0
29x=7
x=7/29 ou aproximadamente 0,2