1))) (4-8,2х)-(3,8х+1)=5; ______ 4-8,2х-3,8х-1=5; ___ 4-1-5=8,2х+3,8х; ___ -2=12х; __ Х=(-2):12; ____ Х=(-2/12)=(-1/6); ___
Проверка; (4- 82/10* (-1/6))- (38/10* (-1/6)+1)= (4- 41/5* (-1/6))- (19/5* (-1/6)+ 1)= (4+ 41/30)- (-19/30+ 1)= (120/30+ 41/30)- (-19/30 +30/30)= (120/30+ 41/30+ 19/30 -30/30)= 180/30- 30/30= 150/30=5. ____________________________________________________________________ 2))) 12= (-6)+ 6* (3х-1,5); ____ 12= (-6)+ 18х-9; _____ 12+6+9= 18х; ______ 27= 18х; ____ Х=27: 18; ____ Х= 1,5; __________ проверка; 12= (-6)+ 6* (3* 1,5 -1,5); _______ 12= (-6)+ 6* (4,5- 1,5); ______ 12= (-6)+ 6* 3; ______ 12= (-6)+ 18; ______ 12=12. ___________________________________________________________________ 3))) 15х-1= 3* (7х-1)-2; _______ 15х-1= 21х-3-2; ______ (-1)+3+2=21х-15х; _______ 4=6х; _____ Х=4:6; ____ Х=4/6= 2/3. Проверка; 15* 2/3 -1= 3* (7* 2/3- 1) -2; ______ 10-1= 3* (14/3- 3/3)-2; _____ 9= 3* 11/3 -2; _____ 9= 33/3 -6/3; _____ 9= 27/3; ______ 9=9. ____________________________________________________________________ 4))) (-8)* (11-2х)+40=3*(5х-4); _____ (-88)+16х+40=15х-12; ____ (-48)+16х=15х-12; _____ 16х-15х=48-12; ______ Х=36. Проверка; (-8)* (11-2*36+40= 3*(5*36-4); (-8)*(11-72)+40= 3*( 180-4); ____ (-8)*(-61)+40= 3*176; ______ 488+40= 528; _______ 528=528. ___________________________________________________________________ 5))) 2х-12*(3-Х)=1+3*(Х+2); _______ 2х-36+12х=1+3х+6; _______ 14х-36=3х+7; ______ 14х-3х=7+36; ______ 11х=43; ______ Х=43:11; ___ Х=43/11= 3 10/11. Проверка; 2* 43/11- 12* (3- 43/11)= 1+3* (43/11)+6; _____ 86/11- 12* (33/11- 43/11)= 1+ 3* (43/11)+6; _____ 86/11- 12* (-10/11)= 1+ 129/11+ 6; _____ 86/11+ 120/11= 11/11+ 129/11+ 66/11; ________ 206/11= 206/11; _____ 18 8/11= 18 8/11.