Question

please with explanation​

Answer 1

1 ) ( 3x + 2y ) - ( 2x - 3y )

= 3x + 2y - 2x + 3y

= 3x - 2x + 2y + 3y

= x + 5y

2 ) 5b−4c+a+2c−3b−4a=−2c+2b−3a

= a+2b−3c+2c−3b−4a=−3s−b−c

= (−2c+2b−3s)−(−3a−b−c)

= −2c+2b−3a+3a+b+c

= 3b−c

3 ) Age of oldest teachers=54 yerars

= Age of youngest teachers = 23 years

= ∴ Range = (54-23) years =31 years

Answer 2

Answer:

B) 4x²+y+6z

C) 2a + b -c

D) 39.7 years

Step-by-step explanation:

1)

$(2 {x}^{2} - 2y + 2z) + (2 {x}^{2} + 3y + 4z)$

$= 2 {x}^{2} - 2y + 2z + 2 {x}^{2} + 3y + 4z$

$= 2 {x}^{2} + 2 {x}^{2} - 2y + 3y + 2z + 4z$

$= 4 {x}^{2} + y + 6z$

2) ( 6a+3b -c) - (4a+2b)

= 6a + 3b -c -4a - 2b

= 6a - 4a +3b - 2b - c

= 2a +b - c

3) Arithmetic mean

= Sum of all numbers/ Total no.s

$\frac{25 + 36 + 45 + 28 + 29 + 32 + 51 + 50 + 54 + 47}{10}$

$= \frac{397}{10}$

$= 39.7 \: \: years$