The line (y=-8x+c) has (y)-intercept (5). What will (y) be at (x=-2)?
Answer and explanation
Correct answer: 21
A y-intercept of 5 means that when x=0, y=5; therefore, c=5. The equation is y=-8x+5. Substituting x=-2 gives y=-8(-2)+5=16+5=21. Option 20 may seem close, but it does not result from adding the constant term 5 correctly. Exam tip: When substituting a negative value of x, check the sign of the product carefully.
Frequently asked questions
What is the correct answer to this question?
21
Why is this the correct answer?
A y-intercept of 5 means that when x=0, y=5; therefore, c=5. The equation is y=-8x+5. Substituting x=-2 gives y=-8(-2)+5=16+5=21. Option 20 may seem close, but it does not result from adding the constant term 5 correctly. Exam tip: When substituting a negative value of x, check the sign of the product carefully.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Introduction to Polynomials. Topic: Slope and y-intercept.
