質問: How do you solve #y=5-x# and #1=4x+3x# using substitution? ==========================================================
回答: #y=4 6/7, x= 1/7# #### Explanation: #y=5-x,1=4x+3x# #:.y=5-x#------(1) #:.7x=1# #x= 1/7# substitute #x= 1/7# in-----(1) #:.y=5-(1/7)# #:.y=35/7-1/7# #:.y=34/7# #:.y=4 6/7# check: substitute #y= 34/7, x=1/7 # in--------(1) #:.34/7=35/7-1/7# #:.34/7=34/7#