The two numbers are -6 and 7
Solution:
Given that eight times a number plus five times another number is -13
The sum of two numbers is 1
To find: the two numbers
Let the two numbers be "a" and "b"
From given information,
Eight times a number plus five times another number = -13
eight times a number "a" + five times another number "b" = -13
8a + 5b = -13 ---- eqn 1
Also given that sum of two numbers is 1
sum of two numbers = 1
a + b = 1 ---- eqn 2
Let us solve eqn 1 and eqn 2 to find values of "a" and "b"
From eqn 2,
a = 1 - b ----- eqn 3
Substitute eqn 3 in eqn 1
8(1 - b) + 5b = -13
8 - 8b + 5b = -13
8 - 3b = -13
-3b = -13 - 8
-3b = -21
b = 7
Substitute b = 7 in eqn 3
a = 1 - 7
a = -6
Thus the two numbers are -6 and 7