Question

Решите уравнения пожалуйстаа) (2\3х-4\5)*15=8б) (5\7-2\3у)*21=1в) 2\3х+7\3х=18г) 7\12м+2\3м-1\4м=7заранее спасибо

Answer 1

А) (2/3х- 4/5)•15= 8
2/3х• 15 - 4/5• 15=8
30/3х- 60/5=8
10х-12=8
10х=8+12
10х=20
Х=20:10
Х=2
Проверка
(2/3• 2- 4/5)•15= (4/3- 4/5)•15= 4/3• 15 - 4/5• 15= 4/1• 5- 4/1• 3= 20- 12= 8

б) (5/7- 2/3у)• 21= 1
5/7• 21- 2/3у•21=1
5/1• 3- 2/1у• 7=1
15- 14у=1
15-1=14у
14=14у
У=14:14
У=1
Проверка
(5/7-2/3•1)•21= (5/7- 2/3)• 21= 5/7• 21- 2/3• 21= 5/1• 3- 2/1• 7= 15-14=1

в) 2/3х+ 7/3х= 18
9/3х=18
3х=18
Х=18:3
Х=6
Проверка
2/3• 6+ 7/3• 6= 2/1• 2+ 7/1• 2= 4+14=18

Г) 7/12м+ 2/3м- 1/4м=7
7/12м+ (2•4)/(3•4)м- (1•3)/(4•3)=7
7/12м+ 8/12м- 3/12м=7
12/12м=7
М=7
Проверка
7/12• 7+ 2/3• 7- 1/4• 7= 7• (7/12+ 2/3- 1/4)= 7• ( 7/12+ (2•4)/(3•4) - (1•3)/(4•3) ) = 7• (7/12+ 8/12 - 3/12)= 7• (12/12)= 7•1=7.

Answer 2

Solving the Equations

Let's solve the given equations step by step:

a) Equation 1: (2/3x - 4/5) * 15 = 8

First, let's solve for x: ``` (2/3x - 4/5) * 15 = 8 2/3x - 4/5 = 8/15 2/3x = 8/15 + 4/5 2/3x = 8/15 + 12/15 2/3x = 20/15 x = (20/15) * (3/2) x = 1.333 * 1.5 x = 2 ``` So, the solution for x in equation 1 is x = 2.

b) Equation 2: (5/7 - 2/3y) * 21 = 1

Now, let's solve for y: ``` (5/7 - 2/3y) * 21 = 1 5/7 - 2/3y = 1/21 -2/3y = 1/21 - 5/7 -2/3y = 1/21 - 15/21 -2/3y = -14/21 y = (-14/21) * (-3/2) y = 2 ``` So, the solution for y in equation 2 is y = 2.

c) Equation 3: 2/3x + 7/3x = 18

Let's solve for x: ``` 2/3x + 7/3x = 18 (2/3 + 7/3)x = 18 (9/3)x = 18 3x = 18 x = 18 / 3 x = 6 ``` The solution for x in equation 3 is x = 6.

d) Equation 4: 7/12m + 2/3m - 1/4m = 7

Now, let's solve for m: ``` 7/12m + 2/3m - 1/4m = 7 (7/12 + 2/3 - 1/4)m = 7 (7/12 + 8/12 - 3/12)m = 7 (12/12)m = 7 m = 7 ``` The solution for m in equation 4 is **m =