Answer: x = - 3.5
Step-by-step explanation:
Rewrite the equation by completing the square.
4x2 + 28x + 49 = 0
Completing the square method :
Divide through by the Coefficient of x^2
x^2 + 7x + (49/4) = 0
a = 1, b = 7, c = 49/4
Move c to the right side of the equation
x^2 + 7x = - 49/4
Complete the square on the left hand side by squaring its half of the x term
(7/2)^2 = (49/4)
Add the output to both sides of the equation
x^2 + 7x + (49/4) = - (49/4) + (49/4)
(x + 7/2)^2 = 0
Square root of both sides
x + 7/2 = 0
x = - 7/2
x = - 3.5
Answer:
a)
28000 + 3000·x = 36000 + 2000·x --> x = 8 years
b)
28000 + 3000·8 = $52000
Lets say the final price of the bike is SP plus 13% VAT. So:
1.13 * SP = 6356.25
SP = 5625
Now SP was after 10% discount on Original Price, say MP. So:
0.9 * MP = 5625
MP = 6250
Therefore, the percent of Marked Price above Cost Price is:
(6250 - 5000) * 100/5000 = 25%
