6. \(y = -4\) Ans: C
\(y = 0x - 4\) represents a horizontal line passing through every point where \(y = -4\).
Distractors: Graph A is vertical line \(x = 4\); Graph B is \(y = 4\); Graph D is vertical line \(x = -4\).
7. \(y = -3x - 2\) Ans: B
\(y\)-intercept is \((0, -2)\) and slope is \(m = -3\). Down 3, right 1 gives \((1, -5)\); or up 3, left 1 gives \((-1, 1)\).
Distractors: Graph A has \(b = +4\); Graph C has \(m = -\frac{1}{3}\); Graph D has positive slope \(m = +3\).
8. \(y = -\frac{3}{4}x - 1\) Ans: A
Start at \(b = -1\). Rise \(-3\) (down 3) and run \(+4\) (right 4) gives \((4, -4)\). Up 3 and left 4 gives \((-4, 2)\).
Distractors: Graph B has positive slope \(+\frac{4}{3}\); Graph C has \(m = +\frac{3}{4}\); Graph D has \(b = +1\).
Algebra 1 • Quiz 2.1 Teacher Guide Page 1 of 2 • Parts 3–5 & Bonus on Page 2 →
Teacher Resource • Answer Key
Page 2 of 2
PART 3: Equation from Graph Identify \(m\) & \(b\)
9. Graph with \((0, -5)\) and \((1, 5)\) Ans: B
\(y\)-intercept \(b = -5\). Slope \(m = \frac{5 - (-5)}{1 - 0} = 10\). Equation: \(\mathbf{y = 10x - 5}\).
10. Graph with \((0, 1)\) and \((2, 3)\) Ans: B
\(y\)-intercept \(b = 1\). Slope \(m = \frac{3 - 1}{2 - 0} = 1\). Equation: \(\mathbf{y = x + 1}\).
11. Graph with \((0, -2)\) and \((-1, 0)\) Ans: B
\(y\)-intercept \(b = -2\). Slope \(m = \frac{0 - (-2)}{-1 - 0} = -2\). Equation: \(\mathbf{y = -2x - 2}\).
12. Graph with \((0, 1)\) and \((1, 5)\) Ans: A
\(y\)-intercept \(b = 1\). Slope \(m = \frac{5 - 1}{1 - 0} = 4\). Equation: \(\mathbf{y = 4x + 1}\).
PART 4: Slope Through Two Points \(m = \frac{y_2 - y_1}{x_2 - x_1}\)
13. \((-5, -9)\) and \((9, 12)\) Ans: A (3/2)
\(m = \frac{12 - (-9)}{9 - (-5)} = \frac{12 + 9}{9 + 5} = \frac{21}{14} = \mathbf{\frac{3}{2}}\).
14. \((-5, -19)\) and \((20, -13)\) Ans: C (6/25)
\(m = \frac{-13 - (-19)}{20 - (-5)} = \frac{-13 + 19}{20 + 5} = \mathbf{\frac{6}{25}}\).
15. \((1, -14)\) and \((-11, -19)\) Ans: A (5/12)
\(m = \frac{-19 - (-14)}{-11 - 1} = \frac{-5}{-12} = \mathbf{\frac{5}{12}}\) (negatives cancel).
PART 5: Equation from Two Points 2-Step Method
16. Through \((0, 2)\) and \((3, 8)\) Ans: A
Step 1: \(m = \frac{8 - 2}{3 - 0} = \frac{6}{3} = 2\).
Step 2: Point \((0, 2)\) gives \(b = 2\) directly.
Equation: \(\mathbf{y = 2x + 2}\).
17. Through \((-2, 7)\) and \((2, -1)\) Ans: A
Step 1: \(m = \frac{-1 - 7}{2 - (-2)} = \frac{-8}{4} = -2\).
Step 2: Solve for \(b\) using \((2, -1)\):
\(-1 = -2(2) + b \implies -1 = -4 + b \implies b = 3\).
Equation: \(\mathbf{y = -2x + 3}\).
⭐ BONUS: Slope Types Key +1 pt each
B1: A (Positive) — Slants upward L to R (\(m > 0\)).
B2: B (Negative) — Slants downward L to R (\(m < 0\)).
B3: C (Zero) — Horizontal line (\(\Delta y = 0\)).
B4: D (Undefined) — Vertical line (\(\Delta x = 0\)).
Score Conversion & Intervention Guide Based on 17 Core Questions
16 – 17 pts
Mastery (94-100%)
14 – 15 pts
Proficient (82-88%)
12 – 13 pts
Basic (70-76%)
< 12 pts
Needs Help (<70%)
• Missed Q1–4: Review rise over run counting and sign rules on grids.
• Missed Q5–8: Practice identifying \(b\) on \(y\)-axis before applying slope.
• Missed Q13–15: Remediate integer subtraction with double negatives.
• Missed Q16–17: Scaffold substituting point \((x, y)\) into \(y = mx + b\).
Algebra 1 • Unit 2 Assessment Materials Slope-Intercept Form Quiz • Complete Answer Key
