(a) How could you calculate 23 x 4 on your calculator if the 4 button is broken? (b) How could you calculate 23 x 21 if the 2 button on your calculator is broken?

23 x 4

=> 23 x (2 + 2)

=> 23 x 2 + 23 x 2

23 x 21

=> 23 x (3 x 7)

=> (23 x 3) x (23 x 7)

true statements:

a) x + y = y + x   ⇒ commutative property of addition

b) (x * y) * z = x * (y * z) ⇒ associative property of multiplication

d) (x + y) + z = x + (y + z) ⇒ associative property of addition

false statements:

c) x - y = y - x   should be: x - y = - y + x

e) (x - y) - z = x - (y - z) should be: (x - y) - z = x - (y + z)

step-by-step explanation:

5x+2x=49

7x=49

x=7. 35 apples