1)3х+7х+18=178 ; 10х+18=178; 10х=178-18; 10х=160; х=160:10; х=16. (2) 6у-2у+2=65; 4у=65-2; 4у= 63; у=63:4; у=15,75. (3)7z+6z-13=130; 13z=130+13; 13z=143; z=143:13; z=11. (4)21t-4t-17=17; 17t=17+17; 17t=34; t=34:17; t=2 теперь другой столбик 1)4x+4x=424; 8x=424; x=53 (2) 15y-8y=714; 7y=714; y=102. (3)9z+z=500; 10z=500; z=50. (4)10k-k=702; 9k=702; k=78. (5) 4L+5L+L=1200; 10L=1200; L=120. (6) 6t+3t-t=6400; 8t=6400; t=800 ВСЕ!