Hello,
I suppose equations are:
x+y=3 (1)
x+2y=9 (2)
(2)-(1)==>y=6
(1)==>x=3-6
x=-3, y=6
Sol={(-3,6)}
If K=C+273.15
and in a. C=200° then K=200+273.15
3x-4y=65
3x=65+4y
x=(65+4y)/3, when y=4
x=(65+4*4)/3
x=(65+16)/3
x=81/3
x=27
Let Susan's present age be x
Now, after 7 years ( her age will become 7 +x then) she'll be 2 as old she was 3 years ago.
Her age 3 years ago must be x-3
Now according to question,
twice Her age 3 years ago = her age after 7 years
now,
2(x-3) = 7+x
2x-6 = 7+x
2x-x =7+6
x = 13
x = 13
Therefore, her age presenr age is 13 years.
I believe this is an equation that could help solve your problem 2.99x+12.99y=43.92
