Form a quadratic equation from the following
information, taking x as width where x e N.
(1) The area of a rectangle whose length is five more
than twice its width is 75.
(ii) Solve the equation and find its length.
Answers
Answered by
0
Answer:
let breadth B = x, L = 5 + 2 x, Area A = 75
area of a rectangle = L × B
(5 + 2x) × x = 75
5 x + 2 x² - 75 = 0
2x² + 5x - 75 = 0 answer (1)
2x² +15x - 10x - 75 = 0
x (2x + 15) - 5 (2x + 15) = 0
(x - 5)(2x + 15) = 0
x - 5 = 0 or x = 5
2x + 15 = 0 or x = -15/2 = -7.5 × [ width can't be negative and -7.5 ∉ N ]
therefore width B = 5 cm
length L = 5 + 2×5 = 15cm
Answered by
1
Answer:
let breadth B = x, L = 5 + 2 x, Area A = 75
area of a rectangle = L × B
(5 + 2x) × x = 75
5 x + 2 x² - 75 = 0
2x² + 5x - 75 = 0 answer (1)
2x² +15x - 10x - 75 = 0
x (2x + 15) - 5 (2x + 15) = 0
(x - 5)(2x + 15) = 0
x - 5 = 0 or x = 5
2x + 15 = 0 or x = -15/2 = -7.5 × [ width can't be negative and -7.5 ∉ N ]
therefore width B = 5 cm
length L = 5 + 2×5 = 15cm
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