Question

the sum of the two square of convective natural number is 13. The quadratic equation of this state ment is
a)x^2+x+13=0
b)x^2-x-6=0
c)x^2+x-6=0
d)x^2-x+25=0

The modal class in the following frequency distribution is
CI. f
5-15 2
15-25 3
25-35 6
35-45 5
45-55 4
a)15-25
b)25-35
c)35-45
d)45-55


please answer it fast
I need step by step explaination
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Answer 1

Answer:

1) let the first number be 'x'

=> other number = x+1 [since, the numbers are consecutive natural numbers]

as per given information,

(x)² + (x+1)² = 13

=> x² + x²+2x+1 = 13 => 2x²+2x-12 = 0 => 2(x²+x-6) = 0

=> x² + x - 6 = 0

2) since the class intervel 25-25 had highest frequency (6)

modal class was c) 25-35