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please help me with these questions !

Answer/Step-by-step explanation:

2. a. 5y - 3 = -18

Add 3 to both sides

5y - 3 + 3 = -18 + 3

5y = -15

Divide both sides by 5

5y/5 = -15/5

y = -3

b. -3x - 9 = 0

Add 9 to both sides

-3x - 9 + 9 = 0 + 9

-3x = 9

Divide both sides by -3

-3x/-3 = 9/-3

x = -3

c. 4 + 3(z - 8) = -23

Apply the distributive property to open the bracket

4 + 3z - 24 = -23

Add like terms

3z - 20 = -23

Add 20 to both sides

3z - 20 + 20 = - 23 + 20

3z = -3

Divide both sides by 3

3z/3 = -3/3

z = -1

d. 1 - 2(y - 4) = 5

1 - 2y + 8 = 5

-2y + 9 = 5

-2y + 9 - 9 = 5 - 9

-2y = -4

-2y/-2 = -4/-2

y = 2

3. First, find the sum of 3pq + 5p²q² + p³ and p³ - pq

(3pq + 5p²q² + p³) + (p³ - pq)

3pq + 5p²q² + p³ + p³ - pq

Add like terms

= 3pq - pq + 5p²q² + p³ + p³

= 2pq + 5p²q² + 2p³

Next, subtract 2pq + 5p²q² + 2p³ from 3p³ - 2p²q² + 4pq

(3p³ - 2p²q² + 4pq) - (2pq + 5p²q² + 2p³)

Apply distributive property to open the bracket

3p³ - 2p²q² + 4pq - 2pq - 5p²q² - 2p³

Add like terms

3p³ - 2p³ - 2p²q² - 5p²q² + 4pq - 2pq

= p³ - 7p²q² + 2pq

4. Perimeter of the rectangle = sum of all its sides

Perimeter = 2(L + B)

L = (5x - y)

B = 2(x + y)

Perimeter = 2[(5x - y) + 2(x + y)]

Perimeter = 2[5x - y + 2x + 2y]

Add like terms

Perimeter = 2(7x + y)

Substitute x = 1 and y = 2 into the equation

Perimeter = 2(7(1) + 2)

Perimeter = 2(7 + 2)

Perimeter = 2(9)

Perimeter = 18 units

5. First let's find the quotient to justify if the value we get is greater than or less than 2.25

7⅙ ÷ 3⅛

Convert to improper fraction

43/6 ÷ 25/8

Change the operation sign to multiplication and turn the fraction by the left upside down.

43/6 × 8/25

= (43 × 8)/(6 × 25)

= (43 × 4)/(3 × 25)

= 172/75

≈ 2.29

Therefore, the quotient of 7⅙ ÷ 3⅛ is greater than 2.25

5=812a+9+3

step 1: simplify both sides of the equation.

5=812a+9+3

5=(812a)+(9+3)(combine like terms)

5=812a+12

5=812a+12

step 2: flip the equation.

812a+12=5

step 3: subtract 12 from both sides.

812a+12−12=5−12

812a=−7

step 4: divide both sides by 812.

812a /812 = -7/812

a= -1/116

so the answer is

a=   -1/116