Effects of Variable X on Expressions

Dora examines how changes in the variable X affect the quadratic expression x^2 + 2x - 15. She identifies which parts of the expression are dependent on X, explaining that terms containing X, such as x^2 and 2X, will change if X changes. The constant term -15 remains unaffected as it does not include X.

What is the main focus of Dora's exploration in the video?

• The effect of variable X on a linear expression

• The effect of variable X on a quadratic expression

• The effect of variable X on a cubic expression

• The effect of variable Y on a quadratic expression

Which parts of the expression x^2 + 2x - 15 are dependent on the variable X?

• The x^2 and 2x terms

• All parts of the expression

• Only the x^2 term

• Only the constant term

If X changes from 1 to 10, which term in the expression x^2 + 2x - 15 will remain unchanged?

• All terms will change

• -15

• 2x

• x^2

What happens to the term 2x if the value of X changes?

• It becomes zero

• It changes proportionally with X

• It remains constant

• It changes inversely with X

Which term is described as the 'major part' in the expression when considering the effect of X?

• -15

• None of the terms

• 2x

• x^2

Why does the constant term -15 not change when X changes?

• Because it is a variable term

• Because it is not multiplied by X

• Because it is dependent on X

• Because it is part of the x^2 term