а)60=100%
15=х
60+15=75
х=75*100/60=125%
125%-100%=25%.
б)75=100%
75-15=60
х=60*100/75=80%.
100%-80%=20%.
в) х - 100%.
х*2
100%*2=200%.
200%-100%=100%.
г) х - 100%.
х:2
100%/2=50%.
100%-50%=50%.
a)
13*(x+3)=65*4
13x+39=260
13x=260-39
13x=221
x=221:13
x=17
================
в)
45*(5x-8)=18*5
225x-360=90
225x = 90+360
225x = 450
x = 450:225
x=2
==============
д)
92*(5+x)=36*23
460+92x=828
92x = 828 - 460
92x = 368
x=368:92
x=4