Теңдеуді шешіңдер; 1) 84а+25а+7=443; 2) 4(9+7х)+21=393; 3) 486: (5х+2)=18; 4) 5(14+b)+6b=158;

1) 84a+25a+7=443
109a=443-7
109a=436
a=4

2) 4(9+7x)+21=393
36+28x+21=393
28x+57=393
28x=393-57=336
x=12

3) 486:(5x+2)=18
5x+2=486:18=27
5x=25
x=5

4) 5(14+b)+6b=158
70+5b+6b=158
11b=158-70
11b=88
b=8