Вычисли(по действиям) ! а) (4.5: 1/5-5/8: 0,75)*2.3-3 2/3*2.3 б) 1 11/15+(5 7/20*4.5+8.9* 4 1/2): 3.75-7/9 ! и уравнение: (0.02y+4 1/2): 1.3+2.7=8.5 !

Вычисли(по действиям)

а) (4.5:1/5-5/8:0,75)*2.3-3 2/3*2.3 = -8 7/25.

{4,5= 4 5/10= 4 (5:5)/10:5)= 4 1/2; 0,75= 75/100=(75:25)/(100:25)=3/4; 2,3= 2 3/10};

1)) 4,5 : 1/5= 4 1/2: 1/5= (4•2+1)/2 •5/1= 9/2• 5/1=45/2;

2)) 5/8: 0,75= 5/8: 3/4= 5/8• 4/3= 5/2• 1/3= 5/6;

3)) (45/2- 5/6)= (45•3)/(2•3)- 5/6= 135/6- 5/6= 130/6;

4)) 130/6•2,3= 130/6• 2 3/10= 130/6• (2•10+3)/10= 130/6• 23/10= 13/6• 23/1= 299/60

5)) 3 2/3• 2,3= (3•3+2)/3 • 2 3/10= 11/3• (10•2+3)/10= 11/3• 23/10= 253/30

6)) 299/60- 253/30= 299/60- (253•2)/(30•2)= 299/60- 506/60= - 207/60= -3 27/60= -3 9/20.

б) 1 11/15+(5 7/20*4.5+8.9* 4 1/2):3.75-7/9 = 18 1/18.

{4,5= 4 5/10= 4 (5:5)/(10:5)= 4 1/2; 8,9= 8 9/10; 3,75= 3 75/100=3 (75:25)/(100:25)= 3 3/4 }

1)) 5 7/20• 4,5= (5•20+7)/20 • 4 1/2= 107/20• (2•4+1)/2= 107/20• 9/2= 963/40;

2)) 8,9• 4 1/2= 8 9/10• (2•4+1)/2= (10•8+9)/10• 9/2= 89/10• 9/2= 801/20

3)) 963/40+ 801/20= 963/40+ (801•2)/(20•2)= 963/40+ 1602/40= 2565/40= 513/8;

4)) 513/8: 3,75= 513/8: 3 3/4= 513/8: (4•3+3)/4= 513/8: 15/4= 513/8• 4/15= 513/2• 1/15= 513/30;

5)) 1 11/15+ 513/30- 7/9= (15•1+11)/15+ 513/30- 7/9= 26/15+ 513/30- 7/9= (26•2)/(15•2)+ 513/30- 7/9= 52/30+ 513/30- 7/9= 565/30- 7/9= (565:5)/(30:5) - 7/9= 113/6- 7/9= (113•3)/(6•3)- (7•2)/(9•2)= 339/18- 14/18= 325/18= 18 1/18.

И уравнение: (0.02y+4 1/2):1.3+2.7=8.5

В десятичных
(0,02у+4 1/2):1,3= 8,5-2,7
(0,02у+4,5 ): 1,3= 5,8
(0,02у+4,5)= 5,8•1,3
0,02у+4,5=7,54
0,02у=7,54-4,5
0,02у= 3,04
У=3,04: 0,02
У=152
Проверка
(0,02•152+4 1/2): 1,3= 8,5-2,7
(3,04+4,5):1,3= 5,8
7,54:1,3=5,8
5,8=5,8

Если надо в дробях

И уравнение: (0.02y+4 1/2):1.3+2.7=8.5
0,02=2/100=(2:2)/(100:2)=1/50; 1,3=1 3/10; 2,7= 2 7/10; 8,5= 8 5/10= 8 (5:5)/10:5)= 8 1/2)

(1/50у+ 4 1/2): 1 3/10 + 2 7/10= 8 1/2
(1/50у+ 4 1/2): 1 3/10= 8 1/2- 2 7/10
(1/50у + (2•4+1)/2) : (10•1+3)/10= (8•2+1)/2- (10•2+7)/10
(1/50у+ 9/2): 13/10= 17/2- 27/10
(1/50у+9/2):13/10= (17•5)/(2•5)- 27/10
(1/50у+ 9/2): 13/10= 85/10- 27/10
1/50у+9/2= 58/10• 13/10
1/50у+9/2= 754/100
1/50у= (754:2)/(100:2) - 9/2
1/50у= 377/50 - (9•25)/(2•25)
1/50у= 377/50- 225/50
1/50у=152/50
У=152/50: 1/50
У= 152/50• 50/1
У= 7600/50
У= 152
Проверка

(1/50•152+ 4 1/2) :1 3/10 +2 7/10= 8 1/2
(1/25• 76+ (4•2+1)/2) : (10•1+3)/10+ (2•10+7)/10= 8 1/2
(76/25+ 9/2) : 13/10 + 27/10= 8 1/2
((76•2)/(25•2) + (9•25)/(2•25)) •10/13+ 27/10= 8 1/2
(152/50+ 225/50) • 10/13+ 27/10= 8 1/2
377/50• 10/13+ 27/10= 8 1/2
29/5• 1/1+ 27/10= 8 1/2
29/5+ 27/10= 8 1/2
(29•2)/(5•2)+ 27/10= 8 1/2
58/10+ 27/10= 8 1/2
85/10= 8 1/2
8 5/10= 8 1/2
8 1/2= 8 1/2.