What is the standard form of the equation (x+4)(x+7)+(x−3)(x+6)=88?
Answer and explanation
Correct answer: 2x²+14x−78=0
Expand the two products: (x+4)(x+7)=x²+11x+28 and (x−3)(x+6)=x²+3x−18. Their sum is 2x²+14x+10, so the equation becomes 2x²+14x+10=88. Bringing 88 to the left gives 2x²+14x−78=0, so option A is correct. Option B stops before subtracting 88. Exam tip: To write a quadratic equation in standard form, bring all terms to one side so that the other side is 0.
Frequently asked questions
What is the correct answer to this question?
2x²+14x−78=0
Why is this the correct answer?
Expand the two products: (x+4)(x+7)=x²+11x+28 and (x−3)(x+6)=x²+3x−18. Their sum is 2x²+14x+10, so the equation becomes 2x²+14x+10=88. Bringing 88 to the left gives 2x²+14x−78=0, so option A is correct. Option B stops before subtracting 88. Exam tip: To write a quadratic equation in standard form, bring all terms to one side so that the other side is 0.
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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