Question

Passage - II: To represent word problem in the form of quadratic equations, suppose the unknown
required quantity can be taken as some of variable x and express the given condition in the form of x to form an equation in x. Then we express the equation in the descending powers of x. Thus standardquadratic equation is ax²+bx+c=0, a≠0.
1.The product of two consecutive even integers is 128, the quadratic equation to find the integers is
A) x² + 2x - 128 = 0
B) x² + x - 128 = 0
C) x² - 2x - 128 = 0
D) x² + 2x = - 128
2.A train travels a distance of 480 km at a uniform speed. If the speed had been 8 km/hr more, then it would have taken 2 hours less to cover the same distance. The quadratic equation is
A) x²+8x+480
B) x²+8x-1920=0
C) x²-x+200=0
D) x²+8x-480=0
3.Sandeep's father is 30 years older than him. The product of their ages 2 years from now will be 400. To find Sandeep's present age, the equation is
A) x²+9x-13 = 0
B) x²+32x+400=0
C) x²+34x-336=0
D) x²-34x+90=0
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Answer 1

Answer:

1) A

2) B

3) C

Step-by-step explanation:

1) x (x+2) =128

x² + 2x = 128

x² + 2x - 128 =0

2) 480 /x - 480/(x+8) = 2

480[ 1/x - 1/(x+8) ] =2

480 [ (x+8-x) / x(x+8) ] =2

480 [ 8 / (x² +8x)] =2

480 × 8 = 2(x² + 8x)

480 ×4 = x² +8x

1920 = x² +8x

x² +8x- 1920 =0

3) Let sandeep age be x

(x+2) (x+32) =400

x² +32x + 2x +64 =400

x²+ 34x +64 -400 =0

x²+ 34x -336 =0

Hope the solution is clear...

Answer 2

s9r of he power......

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