Question

Determinați numărul x ,stiind ca a-b=6 si:
a) x+3×a-3×b=20
b) x×a-x×b+9a-9b=654
c) 7×a-7×b+x=55
d) 13+x-(5×a-5×b)=2011

Answer 1

Determinați numărul x ,stiind ca a-b=6 si:

a) x+3×a-3×b=20 ⇒  x + 3 × (a - b) =20⇒ x + 3×6 = 20⇒ x =20 - 18⇒x = 2

b) x×a-x×b+9a-9b=654⇒x×(a - b) + 9×(a - b) = 654⇒x×6 +9×6 =654⇒6x = 654 - 54⇒x = 600 :6 ⇒x = 100

c) 7×a-7×b+x=55⇒7×(a - b) + x = 55⇒7×6 + x = 55⇒x = 55 - 42⇒ x = 13

d) 13+x-(5×a-5×b)=2011⇒13 + x - 5 × ( a- b) = 2011⇒ 13 + x - 5×6 =2011⇒x = 2011+ 30 -13⇒x = 2028