А)-5 3/28+4 5/12 б)-3 7/12-2 5/12 в)-4/7: (-8/21) - вопрос №525114453284512371225124782173793731 от nasti0902003 25.11.2020 20:12

Question

Математика: А)-5 3/28+4 5/12 б)-3 7/12-2 5/12 в)-4/7: (-8/21) г)7 3/7: (-9 3/7 д)-3 1/9: 2 1/3 е)24/25: (-12)

nasti0902003 · Answer

А) -5 3/28+4 5/12=4 5/12-5 3/28=4-5+5/12-3/28=
-1+35/84-9/84=-1+26/84=-84/84+26/84=-58/84=-29/42
б)-3 7/12-2 5/12=-(3 7/12+2 5/12)=-(5 12/12)=-6
в)-4/7÷(-8/21)=4/7÷8/21=4/7×21/8=1/1×3/2=3/2=1 1/2
г)7 3/7÷(-9 3/7)=-7 3/7÷9 3/7=-52/7÷66/7=-52/7×7/66=-26/1×1/33=-26/33
д)-3 1/9÷2 1/3=-28/9÷7/3=-28/9×3/7=-4/3×1/1=-4/3=-1 1/3
е)24/25÷(-12)=-24/25÷12=-24/25×1/12=-2/25×1/1=-2/25