Solve the following pairs of linear (simultaneous) equations using method of elimination by substitution:
x6+y15=4
x3−y12=434
x6+y15=4(5x+2y)30=45x+2y=1205x=120−2yx=(120−2y)5x3−y12=43413[x−y4]=19413[(120−2y)5−y4]=194(480−13y)20=574480−13y=28513y=195y=15x=(120−2×15)5x=905x=18