Question

y/2+z/3=13 ,y/3-z/4=3 用加减法解下列方程··

Answer 1

y/2+z/3=13 ,y/3-z/4=3

先去分母

3y+2z=78 (1)

4y-3z=36 (2)

(1)*3+(2)*2

9y+6z+8y-6z=78*3+36*2

17y=306

y=18

(1)*4-(2)*3

12y+8z-12y+9z=78*4-36*3

17z=204

z=12

y=18,z=12