Solve the simultaneous equation below
The sum of 2 number is 8, their product is 15. Find the number.
5 answers
5 and 3
nice guess, but Juliet has learned nothing.
X+y=8 ----------(1)
Xy=15 ----------(2)
X+y=8
Y=8-x -----------(3)
Put y=8-x in eqn (1)
xy=15
X(8-x)=15
8x-x^2-15=0
X^2-8x+15=0
(X-5)(x-3)=0
Put x=5 in eqn(1) put x=3 in eqn (1)
X+y=8 x+y=8
5+y=8 3+y=8
Y=8-5 Y=8-3
Y=3 y=5
Hence x & y =3 & 5
Xy=15 ----------(2)
X+y=8
Y=8-x -----------(3)
Put y=8-x in eqn (1)
xy=15
X(8-x)=15
8x-x^2-15=0
X^2-8x+15=0
(X-5)(x-3)=0
Put x=5 in eqn(1) put x=3 in eqn (1)
X+y=8 x+y=8
5+y=8 3+y=8
Y=8-5 Y=8-3
Y=3 y=5
Hence x & y =3 & 5
the equations needed are
x+y = 8
xy = 15
x + 15/x = 8
x^2 - 8x + 15 = 0
(x-5)(x-3) = 0
or, note that for x^2+bx+c=0, the sum of the roots is -b and the product of the roots is c.
x^2-8x+15 = 0
as above
x+y = 8
xy = 15
x + 15/x = 8
x^2 - 8x + 15 = 0
(x-5)(x-3) = 0
or, note that for x^2+bx+c=0, the sum of the roots is -b and the product of the roots is c.
x^2-8x+15 = 0
as above
ok yall stop yall know this girl neeed help bad so stop making stuff complicated. lmao
3 answers