Find two numbers whose sum is -64, if twice the first is 1 more than the second

Answer 1

first one --- x
second one -- y
x+y = -64 ---> y = -x-64

2x = y+1
sub the first into that:
2x = -x-64 + 1
3x = -63
x = -21
y = -(-21) - 64 = -43

the two numbers are -21 and -43

check:
yes , their sum is -64
twice the first = -42
one more than the second = -43+1 = -42
All is good!