Math, asked by haniya7924, 1 year ago

in a class test, the sum of shefali's marks in mathematics and english is 30. had she got 2 marks more in mathematics and 3 marks less in english, the product of the marks would be 210. find the marks

Answers

Answered by pencilbox
24

Answer :

Let Shefali's marks in mathematics be = x

Let Shefali's marks in english be = y

given that - x + y = 30

x = 30-y ------ (1)

(x+2) * (y-3) = 210 ------(2)

substituting 1 in 2

(30-y+2) * (y-3) = 210

(32-y) * (y-3) =210

32y - 96 - y² +3y - 210 = 0

35y - y² - 306 = 0

y² - 35y + 306 = 0

now we can solve this quadratic equation by quadratic formula

x= -b±√b²- 4 ac ÷ 2a

a= 1  ,b= -35 , c=306

x= - (-35)±√35²- 4*(1)*(306) ÷ 2*(1)

x= 35 ±√1225-1224 ÷ 2

x= 35 ± 1 ÷2

x = 35 + 1 ÷2          or       x  =  35 - 1 ÷2

x = 36÷2                  or      x = 34÷2

x= 18      or       x = 17

      so    .... 30 - 18 = 12

              or

                  30 - 17 = 13

marks in marks in mathematics = 12 , marks in english = 18

or

marks in mathematics = 13 , marks in english = 17

hope, it was helpful  

Answered by Anonymous
4

Let the marks of maths = x

Let the marks of english=30-x

━━━━━━━━━━━━━━━

\large\sf{A/C,}

(x+2)(30-x-3)=210

(x+2)(27-x)=210

27x-\sf{{x}^{2}}+54-2x=210

\sf{{-x}^{2}}+27x-2x+54-210=0

\sf{-({x}^{2}}+25x-156)=0

\sf{-{x}^{2}}-25x+156=0

\sf{{x}^{2}}-25x+156=0

\sf{{x}^{2}}-13x-12x+156=0

x(x-13) -12(x-13) =0

(x-12) (x-13) =0

━━━━━━━━━━━━━━━

x-12=0

x=12

x-13=0

x=13

━━━━━━━━━━━━━━━

Shefali got marks in maths = 12

Shefali got marks in English= 30-12=18

OR

Marks in maths = 13

Marks in English= 30-13=17

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