Question

Să se afle necunoscuta,120×a-(1980+520)=3000 ;2245×a×15=200 ;32×645:a=5 ;4249+8×m=898 ;5×a:6+129=231 ;9×(e+15)=810 ;(a-2)+3+4-45:9=15 ;m:3=249rest 2 ;1243:a=21rest 25.​

Answer 1

Explicație pas cu pas:

1) 120×a-(1980+520)=3000

120a-2500=3000

120a=3000+2500=5500

a=5500÷120

a=275/6

2) 2245×a×15=200

33675a=200

a=200÷33675

a=8/1347

3) 32×645÷a=5

20640÷a=5

a=20640÷5

a=4128

4) 4249+8m=898

8m= 898-4249

8m= -3351

m= -3351/8

5) 5a÷6+129=231 |×6

5a+774=1386

5a= 1386-774

5a= 612

a=612/5

6) 9(e+15)=810 |÷9

e+15=90

e= 90-15

e= 75

7) (a-2)+3+4-45÷9=15

a-2+3+4-5=15

a+0=15

a=15

8) m÷3=249 rest 2

m=249×3+2

m=749

9) 1243÷a=21 rest 25

a=(1243-25)÷21

a=58