A student is attempting to evaluate the literal equation below. Which statement best applies to the sample mathematical work shown?
Given: w+ xy + 3x2 = 2 and x = 2 y, find w when y = -2.
Step 1: I first substitute y = -2 into x = 2 y, yielding x = 2(-2).
Step 2: I simplify the expression, resulting in x = 4.
Step 3: I substitute x = 4 and y=-2 into w + xy + 3x2 = 2 and get
w+4(-2)+3(4)2 = 2
Step 4: I use order of operations to simplify and get w - 8+ 48 = 2
So w = -38.
A. The student's substitution in step 1 is invalid or incorrect.
B. The simplification performed in step 2 is invalid or incorrect.
C. Raising 4 to the second power in step 3 before multiplying it by 3 is an invalid or incorrect.
D. The mathematical work is correct as written.

Consider the following geometry problems in 3-space enter t or f depending on whether the statement is true or false. (you must enter t or f -- true and false will not work.) f equation editorequation editor 1. a plane and a line either intersect or are parallel t equation editorequation editor 2. two planes parallel to a third plane are parallel f equation editorequation editor 3. two lines either intersect or are parallel f equation editorequation editor 4. two planes orthogonal to a third plane are parallel f equation editorequation editor 5. two planes orthogonal to a line are parallel f equation editorequation editor 6. two planes either intersect or are parallel f equation editorequation editor 7. two lines orthogonal to a third line are parallel t equation editorequation editor 8. two lines parallel to a third line are parallel t equation editorequation editor 9. two planes parallel to a line are parallel f equation editorequation editor 10. two lines parallel to a plane are parallel f equation editorequation editor 11. two lines orthogonal to a plane are parallel