Home
Class 12
MATHS
Solve the equation 15.2^(x+1)+15.2^(2-x)...

Solve the equation `15.2^(x+1)+15.2^(2-x)=135`

Text Solution

Verified by Experts

This equation rewrite in the form
`30.2^x)+60/(2^(x))=135`
Let `t=2^(x)`
Then `30t^(2)-135t+60=0`
`implies6t^(2)-27t+12=0`
`implies6t^(2)-24t-3t+12=0`
`implies(t-4)(6t-3)=0`
Then `t_(1)=4` and `t_(2)=1/2`
Thus, given equation is equivalen to
`2^(x)=4` and `2^(x)=1/2`
Then `x_(1)=2` and `x_(2)=-1`
Hence roots of the original equation are `x_(1)=2` and `x_(2)=-1`.
Promotional Banner

Topper's Solved these Questions

  • THEORY OF EQUATIONS

    ARIHANT MATHS|Exercise Exercise For Session 1|11 Videos
  • THEORY OF EQUATIONS

    ARIHANT MATHS|Exercise Exercise For Session 2|10 Videos
  • THE STRAIGHT LINES

    ARIHANT MATHS|Exercise Exercise (Questions Asked In Previous 13 Years Exam)|18 Videos
  • THREE DIMENSIONAL COORDINATE SYSTEM

    ARIHANT MATHS|Exercise Exercise (Questions Asked In Previous 13 Years Exam)|44 Videos

Similar Questions

Explore conceptually related problems

Solve the equation 15-x=4

Solve the equation.(9x)/(7-6x)=15

Solve the equation x^(2)+ 2ix+15=0 .

Solve the equation |x^(2)-1|+|2-x^(2)|=1

Solve the equation x(x+2)(x^(2)-1)=-1

Solve the equation *(x)/(3)+1=(7)/(15)

Solve the equation.1.6=(y)/(15),(2x)/(3)=187x-9=16

Solve the inequation: -15lt(39x-2)/5le0

Solve the equation x^(3)-13x^(2)+15x+189=0 if one root exceeds the other by 2 .

ARIHANT MATHS-THEORY OF EQUATIONS-Exercise (Questions Asked In Previous 13 Years Exam)
  1. Solve the equation 15.2^(x+1)+15.2^(2-x)=135

    Text Solution

    |

  2. In the quadratic equation ax^2 + bx + c = 0. if delta = b^2-4ac and al...

    Text Solution

    |

  3. Let S denote the set of all polynomials P(x) of degree lt=2 such th...

    Text Solution

    |

  4. If the roots of x^2-b x+c=0 are two consecutive integers, then b^2-4c ...

    Text Solution

    |

  5. If the equation a(n)x^(n)+a(n-1)x^(n-1)+..+a(1)x=0, a(1)!=0, n ge2, ha...

    Text Solution

    |

  6. If both the roots of the quadratic equation x^2-2kx+k^2+k-5=0 are less...

    Text Solution

    |

  7. Let aa n db be the roots of the equation x^2-10 c x-11 d=0 and those o...

    Text Solution

    |

  8. Let a,b,c be the sides of a triangle. No two of them are equal and lam...

    Text Solution

    |

  9. All the values of m for whilch both the roots of the equation x^2-2m x...

    Text Solution

    |

  10. If the roots of the quadratic equation x^2+p x+q=0 are tan30^0a n dtan...

    Text Solution

    |

  11. Let alpha,beta be the roots of the equation x^2-p x+r=0 and alpha/2,2b...

    Text Solution

    |

  12. If the difference between the roots of the equation x^2+a x+1=0 is les...

    Text Solution

    |

  13. Let a, b, c, p, q be the real numbers. Suppose alpha,beta are the ...

    Text Solution

    |

  14. The quadratic equations x^2""6x""+""a""=""0""a n d""x^2""c x""+""6"...

    Text Solution

    |

  15. How many real solutions does the equation x^7+14 x^5+16 x^3+30 x-560=0...

    Text Solution

    |

  16. Suppose the cubic x^(3)-px+q has three distinct real roots, where pgt0...

    Text Solution

    |

  17. The smallest value of k, for which both the roots of the equation, x^2...

    Text Solution

    |

  18. If the roots of the equation b x^2+""c x""+""a""=""0 be imaginary, ...

    Text Solution

    |

  19. Q. Let p and q real number such that p!= 0,p^2!=q and p^2!=-q. if alph...

    Text Solution

    |

  20. Conder the function f(x)=1+2x+3x^2+4x^3 Let the sum of all distinct ...

    Text Solution

    |

  21. Let alpha and beta be the roots of x^2-6x-2=0 with alpha>beta if an=al...

    Text Solution

    |