Correct answer: A

The correct answer is Each input is paired with exactly one output..

1. Identify the algebraic structure: Determine whether the problem asks about an expression, equation, inequality, function, pattern, or model.
2. Apply the algebraic rule: A function assigns exactly one output to each input, although several inputs may share the same output.
3. Check the result: The correct choice is Each input is paired with exactly one output..

Correct answer: B

The correct answer is 2.

1. Identify the algebraic structure: Determine whether the problem asks about an expression, equation, inequality, function, pattern, or model.
2. Apply the algebraic rule: Use the slope formula: (6 - 2) / (3 - 1) = 4 / 2 = 2.
3. Check the result: The correct choice is 2.

Correct answer: C

The correct answer is -5.

1. Identify the algebraic structure: Determine whether the problem asks about an expression, equation, inequality, function, pattern, or model.
2. Apply the algebraic rule: In y = mx + b, b is the y-intercept. Here b = -5.
3. Check the result: The correct choice is -5.

Correct answer: D

The correct answer is 9.

1. Identify the algebraic structure: Determine whether the problem asks about an expression, equation, inequality, function, pattern, or model.
2. Apply the algebraic rule: Substitute 4 for x: y = 2(4) + 1 = 9.
3. Check the result: The correct choice is 9.

Correct answer: A

The correct answer is $y=3x+5$.

1. Identify the algebraic structure: Determine whether the problem asks about an expression, equation, inequality, function, pattern, or model.
2. Apply the algebraic rule: The y-values increase by 3, so the slope is 3, and the value at x = 0 gives an intercept of 5.
3. Check the result: The correct choice is $y=3x+5$.

Correct answer: B

The correct answer is 4.

1. Identify the algebraic structure: Determine whether the problem asks about an expression, equation, inequality, function, pattern, or model.
2. Apply the algebraic rule: In y = kx, the coefficient k is the constant of proportionality, so k = 4.
3. Check the result: The correct choice is 4.

Correct answer: C

The correct answer is A horizontal line..

1. Identify the algebraic structure: Determine whether the problem asks about an expression, equation, inequality, function, pattern, or model.
2. Apply the algebraic rule: A horizontal line has no vertical change as x changes, so its slope is 0.
3. Check the result: The correct choice is A horizontal line..

Correct answer: D

The correct answer is A vertical line..

1. Identify the algebraic structure: Determine whether the problem asks about an expression, equation, inequality, function, pattern, or model.
2. Apply the algebraic rule: A vertical line has a zero change in x, so the slope formula would require division by zero.
3. Check the result: The correct choice is A vertical line..

Correct answer: A

The correct answer is $y=3x+2$.

1. Identify the algebraic structure: Determine whether the problem asks about an expression, equation, inequality, function, pattern, or model.
2. Apply the algebraic rule: In slope-intercept form y = mx + b, m = 3 and b = 2.
3. Check the result: The correct choice is $y=3x+2$.

Correct answer: B

The correct answer is 4.

1. Identify the algebraic structure: Determine whether the problem asks about an expression, equation, inequality, function, pattern, or model.
2. Apply the algebraic rule: Set y equal to zero: 0 = 2x - 8, so 2x = 8 and x = 4.
3. Check the result: The correct choice is 4.