Question

求过程和答案！！。

Answer 1

4D+3E+F+25=0 ---(1)
5D+2E+F+29=0 ---(2)
D+F+1=0 ---(3)

in (3),

D+F+1=0
D=-F-1 ---(4)
sub (4) into (1),
4(-F-1)+3E+F+25=0
3E-3F+21=0
E=F-7 ---(5)
sub (4) & (5) into (2),
5(-F-1)+2(F-7)+F+29=0
-5F-5+2F-14+F+29=0
-2F+10=0
F=5
sub F=5 into (3),
D+5+1=0
D=-6
sub F=5 & D=-6 into (1),
-24+3E+5+25=0
3E=-6
E=-2

so,
D=-6
E=-2
F=5

Answer 2

Answer 3

Answer 4