.(1)3x=4(x-y) x-8(x-y)=5 (2)2a+3b=4 3a-5b=13

问题描述:

.(1)3x=4(x-y) x-8(x-y)=5 (2)2a+3b=4 3a-5b=13

1) 3x=4(x-y) 去括号并移项 化简得 x=4y
x-8(x-y)=5 去括号并移项 8y-7x=5
两个式子结合:x=-1 ,y=-1/4
(2) 2a+3b=4.(1)
3a-5b=13.(2)
(1)*5+ (2)*3得 19a=59,a= 19/59 ,将a带入 (1)得
b= -14/19