What is the standard form ax^2+bx+c=0) of the equation (x+2)(x+5)+(x-1)(x+4)=609?
Answer and explanation
Correct answer: 2x^2+10x-54=0)
Expand the two products: (x+2)(x+5)=x^2+7x+10) and (x-1)(x+4)=x^2+3x-4). Their sum is 2x^2+10x+6). Bringing 60 to the left gives 2x^2+10x+6-60=0), which simplifies to 2x^2+10x-54=0). Option B stops before subtracting 60, while option C does not represent the correctly simplified equation. Exam tip: In standard form, collect all terms on one side and write zero on the other side.
Frequently asked questions
What is the correct answer to this question?
2x^2+10x-54=0)
Why is this the correct answer?
Expand the two products: (x+2)(x+5)=x^2+7x+10) and (x-1)(x+4)=x^2+3x-4). Their sum is 2x^2+10x+6). Bringing 60 to the left gives 2x^2+10x+6-60=0), which simplifies to 2x^2+10x-54=0). Option B stops before subtracting 60, while option C does not represent the correctly simplified equation. Exam tip: In standard form, collect all terms on one side and write zero on the other side.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Quadratic Equations. Topic: Introduction to Quadratic Equations.
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