Question

已知4a^2-3b^2=7,3a^2+2b^2=15,求代数式14a^2-2b^2的值

Answer 1

4a^2-3b^2=7

3a^2+2b^2=15,

两式相加：

7a²-b²=22

14a^2-2b^2

=2(7a²-b²)

=2*22

=44