Question

rezolva urmatoarele cerinte
afla numarul a daca ab+ac=520 si b+c=52
afla numarul a daca ab-ac=45 si b-c=9
afla suma b+c daca ab+ac+70=170 si a=25
afla diferenta b-c daca ab-ac-48=2 si a=10

Answer 1

a(b+c)=520
a×52=520
a=520:52=10
a(b-c)=45
a×9=45
a=45:9=5
a(b+c)+70=170
25(b+c)=170-70
b+c=100:25=4
a(b-c)-48=2
10(b-c)=2+48
b-c=50:10=5

Answer 2

ab+ac =520
b+c =52
a×b+a×c = a×(b+c)=520
a×52=520
a= 520:52
a= 10


ab-ac = 45
b-c = 9
ab- bc = a×( b-c) =45
a×9 =45
a= 45:9
a= 5