Question

20. 4+ (3х-7) = 9 21. 3-(5-у) = 11 22. 3(x+2) = 4x+1 23. 4(x-2 )= - (3x-6) 24. 3(х-5)+7 = 5х-3 25. 8a+(4a-5) = 31; 26. -13-(5a+42) = 6a 27. 90+23х = 12+10х 28. 3∙(5х-16) = -18

Answer 1

------------========--------'

Answer 2

20. To solve 4 + (3x - 7) = 9, you can first simplify the left side by combining like terms:

4 + 3x - 7 = 9 3x - 3 = 9

Then, you can isolate the variable by adding 3 to both sides:

3x = 12

Finally, divide both sides by 3:

x = 4

So the solution is x = 4.

21. To solve 3 - (5 - y) = 11, you can start by simplifying the expression inside the parentheses:

3 - 5 + y = 11

Then, simplify the left side:

-2 + y = 11

Finally, isolate the variable by subtracting -2 from both sides:

y = 13

So the solution is y = 13.

22. To solve 3(x + 2) = 4x + 1, you can start by distributing the 3 on the left side:

3x + 6 = 4x + 1

Then, isolate the variable by subtracting 3x from both sides:

6 = x + 1

Finally, isolate the variable by subtracting 1 from both sides:

x = 5

So the solution is x = 5.

23. To solve 4(x - 2) = -(3x - 6), you can start by distributing the -1 on the right side:

4x - 8 = -3x + 6

Then, isolate the variable by adding 3x to both sides:

7x - 8 = 6

Finally, isolate the variable by adding 8 to both sides:

7x = 14

So the solution is x = 2.

24. To solve 3(x - 5) + 7 = 5x - 3, you can start by distributing the 3 on the left side:

3x - 15 + 7 = 5x - 3

Then, simplify the left side by combining like terms:

3x - 8 = 5x - 3

Next, isolate the variable by subtracting 3x from both sides:

-8 = 2x - 3

Finally, isolate the variable by adding 3 to both sides:

-5 = 2x

So the solution is x = -2.5.

25. To solve 8a + (4a - 5) = 31, you can start by simplifying the expression inside the parentheses:

8a + 4a - 5 = 31

Then, simplify the left side by combining like terms:

12a - 5 = 31

Next, isolate the variable by adding 5 to both sides:

12a = 36

Finally, divide both sides by 12:

a = 3

So the solution is a = 3.

26. To solve -13 - (5a + 42) = 6a, you can start by simplifying the expression inside the parentheses:

-13 - 5a - 42 = 6a

Then, simplify the left side by combining like terms:

-55 - 5a = 6a

Next, isolate the variable by adding 5a to both sides:

-55 = 11a

Finally, divide both sides by 11:

a = -5

So the solution is a = -5.

27. To solve 90 + 23x = 12 + 10x, you can start