Answer: first number = -3.3846 and second number = 69.3843
Step-by-step explanation: Let the first numbers be x and the second number be y.
x + y = 21.5x + 2y = 66
splitting the above equation into simultaneous equations, we have
x + y = 21.5x + 2y ...........................eqn 1
21.5x + 2y = 66 ...............................eqn 2
from eqn 1, we collect like terms and simplify and we have
21.5x - x +2y -y = 0
20.5x + y = 0 .............................eqn 3
solving eqns 2 and 3 simultaneously
20.5x + y = 0
21.5x + 2y = 66
multiply eqn2 by the coefficient of y in equ 3 and multiply eqn 3 by the coefficient of y in eqn 2, we have
20.5x + y = 0 x 2 ..........................eqn 4
21.5x + 2y = 66 x 1 ...........................eqn 5
41x + 2y = 0 ........................... eqn 6 (result of eqn 4)
21.5x + 2y = 66 .......................eqn 7 (result of equation 5)
subtract eqn 7 from eqn 6, we have
19.5x = -66
x = -66/19.5 = -3.3846
substituting x into eqn 3 we have
20.5 * (-3.3846) + y = 0
-69.3843 + y = 0
When a number crosses the equality sign, the sign on it changes, therefore we will have
y = 66.3843
Hence, the two numbers are -3.3846 and 66.3843