Question

Va rog ajutatima dau coroana!!!!


Determinați numărul x, știind că a – b = 6 și:
a) x + 3 ⋅ a – 3 ⋅ b = 20 ;
c) 7 ⋅ a – 7 ⋅ b + x = 55 ;
b) x ⋅ a– x ⋅ b + 9a – 9b = 654 ;
d) 13 + x– (5 ⋅ a – 5 ⋅ b) = 2 011.

Answer 1

a)
$x + 3 \times a - 3 \times b = 20 \\ x + 3a - 3b = 20 \\ a - b = 6 = > 3a - 3b = 18 \\ x + 18 = 20 = > x = 2$
b)
$7a - 7b + x = 55 \\ 7a - 7b = 42 \\ 42 + x = 55 = > x = 13$
c)
$xa - xb + 9a - 9b = 654 \\ 9a - 9b = 54 \\ x(a - b) + 54 = 654 \\ x \times 6 = 600 \\ x = 100$
$13 + x - (5a - 5b) = 2.011 \\ 5a - 5b = 30 \\ x - 30 = 1.998 \\ x = 1968$