Question

the sum of two numbers is 45 and the difference is 17 what are the numbers

Answer 1

let two no be x and y
x+y=45
x-y=17
solve thse to get no .

Answer 2

let xand y be the numbers since they are unknown
their sum which is x+y=45-----equation 1
their difference is x-y=17------equation2
from equation 2
x-y=17
x=17+y
substitute xinyto equation 1
17+y+y=45
17+2y=45
make y the subject
2y=45-17
y=28/2
y=14
since x=17+y
x=17+14
x=31

Answer 3

x + y = 45 ---> x = 45 - y
x - y = 17

now sub 45 - y in for x in the second equation...
x - y = 17
45 - y - y = 17 (combine like terms)
45 - 2y = 17
45 - 17 = 2y
28 = 2y
14 = y

now sub 14 in for y in either of the equations...
x + y = 45
x + 14 = 45
x = 45 - 14
x = 31

check...
x + y = 45
31 + 14 = 45
45 = 45 (correct)

check by the other equation...
x - y = 17
31 - 14 = 17
17 = 17 (correct)

ANSWER : The two numbers are 31 and 14