1. 1) 9х-8= 4х+12
9х-4х=12+8
5х=20
х=4
2) 9-7(х+3)=5-4х
9х-21=5-4х
13х=26
х=2
7=28x^2,
x^2=1/4,
x1=-1/2,
x2=1/2.