Home › ICSE Class 10 › mathematics › Quadratic Equations › Which quadratic has roots whose sum is 7 and pro…
Which quadratic has roots whose sum is 7 and product is 12?
Ax^2 - 7x + 12 = 0
Bx^2 + 7x + 12 = 0 with same coefficients
Cx^2 - 7x - 12 = 0 with negative constant
Dx^2 + 7x - 12 = 0 with negative constant
Answer & Solution
Correct answer: A. x^2 - 7x + 12 = 0
1. For x^2 + px + q = 0, sum of roots = -p, product = q.
2. Sum = 7 means -p = 7, so p = -7.
3. Product = 12 means q = 12.
4. The equation is x^2 - 7x + 12 = 0.
_Source: Selina Concise Mathematics Class 10, Ch 5 Quadratic Equations (Mistral OCR'd PDF), section on root-coefficient relations_
Related questions
If x² − 9 = 0, then x =Roots of x² − 5x + 6 = 0 are:Two times a number, added to the square of that number, gives 3. What could the number be?If 4x² + 12x + 9 = 0 and 2y² + 11y + 14 = 0, establish the relation between x and y.If x² − 6x + 9 = 0 and y² − 3y − 18 = 0, what is the relation between x and y?If x² − 15x + 56 = 0 and y = √64, establish the relation between x and y.The area of a rectangle is 60 sq cm and length exceeds breadth by 4 cm. Breadth isSolve by completing the square: x^2 + 6x + 5 = 0. Roots are