Question

x+y+z+t=8
2y+z+t=2
2z+t=5
2t=5

Answer 1

$I) x+y+z+t=8 \\ II) 2y+z+t=2 \\ III) 2z+t=5 \\ IV) 2t=5 \\ \\ IV)2t = 5 \\ t=5/2 \\ t=2,5 \\ \\ III)2z +t = 5 \\ 2z + 2,5 = 5 \\ 2z=2,5 \\ z=2,5/2 \\ z=1,25 \\ \\ II)2y+z+t=2 \\ 2y+1,25+2,5=2 \\ 2y=-1,75 \\ y=-1,75/2 \\ y=-0,875 \\ \\ I) x+y+z+t=8 \\ x+(-0,875)+1,25+2,5=8 \\ x-0,875+3,75=8 \\ x=5,125$