Work through the set before checking solutions. Guide question labels match the source lesson references. 3 written responses appear below the question bank, with model answers for self-review; these are not automatically graded.
Guide question labels stay the same when the order changes. Check answers when you are ready to review.
Written self-checks are below the question bank and are excluded from the automatic score.
Written responses are self-review exercises.
Saved on this browser and device; clearing browser data removes progress.
The drill
Your practice is saved on this device.
Question 2
Guide question E3.2
Evaluate −2a2 + 5a when a = −3.
Enter an integer, decimal or fraction without units. Use up to 5 characters, or 6 including a leading minus.
Why this answer
−33. Substitute a = −3 into the original expression:
−2a2 + 5a = −2(−3)2 + 5(−3) = −18 − 15 = −33.
The square applies to the substituted value −3, while the coefficient −2 remains outside the square. Repair: Example 3.02.
If 4(x + 1) = 20, what is the value of (x + 1)2 − 3?
Enter an integer, decimal or fraction without units. Use up to 5 characters, or 6 including a leading minus.
Why this answer
22. Divide 4(x + 1) = 20 by 4 to obtain the entire group x + 1 = 5. Substitute the group directly into the target: (x + 1)2 − 3 = 52 − 3 = 22. Solving for x = 4 also works but is not needed. Repair: Example 3.14.
Write your complete response before opening the model answer. Compare both your answer and your reasoning.
Guide question E3.1
In −7x2 + x − 3, what is the coefficient of x and what is the constant term?
Show model answerHide model answer for question E3.1
Coefficient of x: 1; constant term: −3. In −7x2 + x − 3, the term x means 1x. The coefficient −7 belongs to x2, not to x. The term independent of x is −3, including its sign. Repair: Example 3.01.
Guide question E3.3
Simplify 3(2x − 5) − 2(x + 4).
Show model answerHide model answer for question E3.3
The second constant is −8, not +8. At x = 0, both the original expression and the simplified expression equal −23, a useful check on the constants. Repair: Example 3.05.
Guide question E3.4
Simplify , and state the original restriction on x.
Show model answerHide model answer for question E3.4
x + 5, forx ≠ 5. Factor x2 − 25 = (x − 5)(x + 5), then divide out x − 5 only when it is nonzero. The original expression remains undefined at x = 5 even though the simpler formula x + 5 is defined there. Equivalent values must be compared on the original domain. Repair: Example 3.08.
After the exit check
If the final answer is wrong, mark the first step that failed: identifying the coefficient, substituting a signed value, distributing through a group, canceling a factor, or recognizing the requested expression. Repair that step on a new problem before adding more complexity.
Section 3 readiness
You should recognize signed coefficients, substitute into powers accurately, distribute to every term, distinguish an expression from an equation, and preserve domain restrictions when canceling a factor. One matching numerical test does not prove an identity.