Х + 19/4 = 7
х = 7 - 19/4
х = (28-19)/4
х = 9/4
х = 2 1/4
х = 2,25
80/11 - у = 13/4
-у = 13/4 -80/11
у = 80/11 -13/4
у = (320 - 143)/44
у = 177/44
у =4 1/44
3x-15=x+3
3x-x=15+3
2x=18
x=18÷2
x=9
а) 16:24= 2*8:3*8=2:3
б) 121:33= 11*11:3*11=11:3
в)1,4:2,1= 0.7*2:0.7*3=2:3
г)1,5:0,6=5*0.3:2*0.3=5:2
<span>д) 1/2 : 1/3 = 3/6 : 2/6 = 3*1/6 : 2*1/6 = 3:2</span>
<span>е) 1 1/5 : 2/5 = 6/5 : 2/5 = 2/5*3 : 2/5 = 3:1</span>
-4(5c-2b)+5(4c-3d)=-20c+8b+20c-15d=8b-15d