若方程组3x+2y=m+1 4x+3y=m-1的解满足x扫码下载作业帮拍照答疑一拍即得
问题描述:
若方程组3x+2y=m+1 4x+3y=m-1的解满足x 扫码下载作业帮
拍照答疑一拍即得
答
3x+2y=m+1....①
4x+3y=m-1...②
①×4-②×3:-y=m+7,即y=-m-7
①×3-②×2:x=m+5,
m+52mm
答
组
3x+2y=m+1
4x+3y=m-1
x+y = -2 3x+3y = -6
y = -6-m-1 = -7-m
x = -2 +7 +m = m +5
的解满足x
答
3x + 2y = m + 1 ①
4x + 3y = m - 1 ②
7×① - 5×② 得到:
7(3x + 2y) - 5(4x + 3y) = 7(m + 1) - 5(m - 1)
21x+14y-20x-15y=7m+7-5m+5
x - y = 2m +12
x
答
若方程组3x+2y=m+1(1) 4x+3y=m-1(2)的解满足x
9x-8x=3(m+1)-2(m-1);
x=m+4;
带入(1)得:
3m+12+2y=m+1;
2y=-2m-11;
y=-m-11/2;
∴m+4<-m-11/2;
2m<-19/2;
∴m<-19/4;