1) 84a+25a+7=443
109a=443-7
109a=436
a=436/109
a=4
2) 4(9+7x)+21=393
36+28x+21=393
28x=393-36-21
28x=336
x=336/28
x=12
3) 486/(5x+2)=18
486=18(5x+2)
486=90x+36
90x=486-36
90x=450
x=450/90
x=5
4) 5(14+b)+6b=153
70+5b+6b=153
11b=153-70
11b=83
b=83/11
b=7,54545454545
1) 84a+25a+7=443
109a=443-7
109a=436
a=436/109
a=4
2) 4(9+7x)+21=393
36+28x+21=393
28x=393-36-21
28x=336
x=336/28
x=12
3) 486/(5x+2)=18
486=18(5x+2)
486=90x+36
90x=486-36
90x=450
x=450/90
x=5
4) 5(14+b)+6b=153
70+5b+6b=153
11b=153-70
11b=83
b=83/11
b=7,54545454545