library(openxlsx)

dat<-read.xlsx("http://kanggc.iptime.org/book/data/macro-islm-e.xlsx")

A<-as.matrix(dat)

H<-matrix(c(0,0,200,200,100,100,0,1000), nrow=8)
H
X<-t(solve(A)%*%H)
XV<-as.vector(X)
names(XV)<-c("Y=","C=","I=","G=","T=","r=","Md=","Ms=")
XV

GH<-matrix(c(0,0,200,200,150,100,0,1000), nrow=8)
GX<-t(solve(A)%*%GH)
GXV<-as.vector(GX)
names(GXV)<-c("Y=","C=","I=","G=","T=","r=","Md=","Ms=")
GXV

GM<-(GXV[1]-X[1,1])/(GXV[4]-H[5,1])
names(GM)<-c("dY/dG=")
GM

MH<-matrix(c(0,0,200,200,100,100,0,1200), nrow=8)
MX<-t(solve(A)%*%MH)
MXV<-as.vector(MX)
names(MXV)<-c("Y=","C=","I=","G=","T=","r=","Md=","Ms=")
MXV

MM<-(MXV[1]-X[1,1])/(MXV[8]-H[8,1])
names(MM)<-c("dY/dM=")
MM