Question

Daca a²-b²=21 si a+b=7.Atunci a-b este egal cu ..?Va rogg.. imi trebuie acum

Answer 1

a²-b²=(a-b)(a+b)=21⇒a-b=$\frac{21}{a+b}= \frac{21}{7}=3$

Answer 2

a²-b²=(a+b)(a-b) =>7*(a-b)=21 a-b=21:7 a-b=3