Question

pe 4 va rog rpd!!!!!
si la 6 pe d

Answer 1

4.

a) b + c = 50 ; a = 2

ab + ac = ?

ab + ac = a × (b + c)⇒ = 2 × 50 = 100

b)  xy + xz +15 = ?  daca  x= 9 si y + z = 11

xy + xz +15 = x × ( y +z ) + 15 = 9 × 11 + 15 = 99 + 15 = 114

c) ab - ac daca a = 7  si b - c = 100

ab - ac = a × (b - c) = 7 × 100 = 700

d) 5xy + 5xz +21 = ?  daca x = 4  si y + z = 100

5x × ( y + z ) = 5 × 4 × 100 = 20 × 100 = 200

6.

d)

101 + 202 + 303 + ...... + 909 + 1010 + ... + 9898 + 9899=

101 × (1 + 2 + 3 + 4 +...+ 99) = 101 × [99 × (99 + 1)]:2]= 101 × 4950 = 499 950