Final answer:
The correct equation for multiplying -4.2 by 2 is -4.2 × 2 = -8.4, which is not listed in the provided options. Furthermore, equations A (y = -3x) and B (y = 0.2 + 0.74x) from the provided examples are linear, as they can be written in the form y = mx + b.
Step-by-step explanation:
The equation for multiplying -4.2 by 2 is -4.2 × 2. We can use the rule that when two numbers with opposite signs multiply, the answer has a negative sign. Therefore, multiplying a negative number by a positive number will result in a negative product. Following this rule:
-4.2 × 2 = -8.4
None of the options A (-8), B (-4), C (4.2), or D (8) in your question are correct, as the answer is actually -8.4.
12.1 Linear Equations:
Regarding your reference to linear equations, the equations that are linear are:
- A. y = -3x
- B. y = 0.2 + 0.74x
These can be identified as linear because they can be rearranged to the standard form of a linear equation, which is y = mx + b, where m represents the slope and b represents the y-intercept. Option C, y = -9.4 - 2x, is also linear as it fits the same form. Therefore, the correct answer is D. A and B, as these both represent linear equations.