Question

Find two numbers with a sum of 20 and a difference of 14.
A. 4 and 18
B. –3 and –17
C. 2 and 16
D. 3 and 17

Answer 1

x+y=20
x-y=14

Answer 2

Add both equations

Answer 3

try to add the numbers in each answer and see which one gets you 20,
try to subtract the numbers in each answer to see what gives you 14.

Answer 4

@Altig But it isn't the right way to solve.

Answer 5

i know, but i think some people, like myself, have issues translating it to algebra. it's always helped me to use alternative ways to get the answer.

if it helps to understand what needs to be done, then it doesn't seem wrong to me

Answer 6

Yes, checking options is not wrong and perhaps a very useful tool in competitive mathematics.