Respuesta :
Answer:
D
Step-by-step explanation:
Given the 2 equations
a + b = 2 → (1)
a - b = - 4 → (2)
Add the equations term by term to eliminate b
2a + 0 = - 2
2a = - 2 ( divide both sides by 2 )
a = - 1
Substitute a = - 1 into (1) and solve for b
- 1 + b = 2 ( add 1 to both sides )
b = 3
Then
ab = - 1 × 3 = - 3 → D
Answer:
option d
Step-by-step explanation:
a+b=2. ,. a-b = -4
a= 2-b
substituting values, we get
(2-b) - b = -4
2 -b -b =-4
2 -2b =-4
-2b = -4-2
2b= 6
b =3
a = 2-3
a= -1
ab = 3×-1
ab = -3