Respuesta :
Answer:
P= $29 and D = -$30
Step-by-step explanation:
4D + 5P = $25
5P = $25 - 4D
P = ($25 - 4D)/5 equation(i)
Noe substitute the value of P
3D + 4P = $26
3D + 4($25 -4D)/5 = $26
3D*5 + ($100 -16D)/5 =$26*5
15D + $100 - 16D =$130
-D = $130 - $100
D = -$30
Again substitute the vale of D in equation(i)
P = ($25 + 4D)/5
=$25 + 4*$30/5
=$25 + $120/5
=-$145/5
=$29
Answer:
P = 29, D = - 30
Step-by-step explanation:
Given the 2 equations
4D + 5P = 25 → (1)
3D + 4P = 26 → (2)
Multiplying (1) by 3 and (2) by - 4 and adding the result will eliminate D
12D + 15P = 75 → (3)
- 12D - 16P = - 104 → (4)
Add (3) and (4) term by term to eliminate D
0 - P = - 29
- P = - 29 ( multiply both sides by - 1 )
P = 29
Substitute P = 29 into either of the 2 equations and solve for D
Substituting into (1)
4D + 5(29) = 25
4D + 145 = 25 ( subtract 145 from both sides )
4D = - 120 ( divide both sides by 4 )
D = - 30