Răspuns:
a)13
f)-52
i)134,8
j)6
Explicație pas cu pas:
a)310-a*(100-30*3)=280
310-a*(100-90)=280
310-a*10=280
-10a=180-310
-10a=-130
a=13
f)110-[a-15*(252-15*16)]=18
110-[a-15*(252-240)]=18
110-(a-15*12)=18
110-(a-180)=18
110-(-18)=a+180
128=a+180
128-180=a
a=-52
i)8-[6400/16-(360-a*2)*5]/20=3
8-[400-(360-2a)*5]/20=3
8-[400-(1800-10a)]/20=3
8-(400-1800+10a)/20=3
8-(-1400+10a)/20=3
(8+1400-10a)/20=3
(1408-10a)/20=3/1 ==> partea de jos inmultim la 20 aducem la numitor comun
(1408-10a)/20=60/20
adica: 1408-10a=60
-10a=60-1408
-10a=-1348
a=-1348/-10
a=134,8
j)[(36-46/2*0)+(a*7-3*12)]/7=6
[(36-23*0)+(a*7-3*12)]/7=6
[(36-0)+(a*7-36)]/7=6
[36+(7a-36)]/7=6
(36+7a-36)/7=6
7a/7=6
a=6
