Question

方程组：a-b+c=0 4a+2b+c=3 25a+5b+c=60 的解是：a=?b=?c=?

Answer 1

a-b+c=0 (1)

4a+2b+c=3 (2)

25a+5b+c=60 (3)

(2)-(1)=3a+3b=3 (4)

(3)-(1)=24a+6b=60 (5)

(5)-2*(4)=18a=54

a=3

代入（4）b=-2

代入（1）c=-5