Question

) 5/7у – 24 = 8/21у – 15 в) 0,6 (5х – 7) = 3 (0,4х + 6,4)

Answer 1

1) 5/7у-24=8/21у-15
5/7у-8/21у=24-15
15/21у-8/21у=9
7/21у=9
у=9:7/21
у=9 * 21/7
у=189/7
у=27

2)0,6(5х-7)=3(0,4х+6,4)
3х-4,2=1,2х+19,2
3х-1,2х=19,2+4,2
1,8х=23,4
х=23,4:1,8
х=13

Answer 2

Let's solve the given equations step by step:

a) To solve the equation 5/7у - 24 = 8/21у - 15, we can start by eliminating the fractions. To do that, we can multiply the entire equation by the least common denominator (LCD), which in this case is 21:

21 * (5/7у - 24) = 21 * (8/21у - 15)

Simplifying, we get:

3у - 504 = 8у - 315

Next, let's isolate the terms with у on one side of the equation. We can do this by moving the term with 3у to the right side and the constant terms to the left side:

8у - 3у = 504 - 315

5у = 189

Finally, divide both sides of the equation by 5 to solve for у:

у = 189/5

b) For the equation 0.6(5х - 7) = 3(0.4х + 6.4), we can start by distributing the coefficients:

3х - 4.2 = 1.2х + 19.2

Next, let's isolate the terms with х on one side of the equation. We can do this by moving the term with 1.2х to the left side and the constant terms to the right side:

3х - 1.2х = 19.2 + 4.2

1.8х = 23.4

Finally, divide both sides of the equation by 1.8 to solve for х:

х = 23.4/1.8

Simplifying the division, we get:

х ≈ 13