The slope is 5.2, so = 5.2x + The is still unknown. y b. y-intercept Possible response: A point on a line is a solution to the equation, so when substituting the and into the equation, the equation is still true. x- y-values Substituting = 9 and = 98.4 into the equation, the equation becomes 98.4 = y y 5.2(9) + After solving, = 51.6 and = 5.2x + 51.6. b. b y The equation is exact and the units for the are grams. y-intercept Starting with 140 = 5.2x + 51.6, the solution becomes = 17 days. x 2-79. See below: = 5 y –3x – = 0.5x 14 y – 2-80. Mt. Everest was 8750.05 meters tall in the year 0; = 0.05x + 8750.05. The units y for are years and for are meters. The answer should be carried to the hundredths m b place because 5 cm is .05 m. 2-81. See Suggested Lesson Activity for possible answers. 2-82. See below: = 1.5x + 0.5 y Answers vary, but solutions should lie on = 1.5x + 0.5. Possible points: (0, 0.5), y (1, 2), (10, 15.5) 2-83. Find solutions in bold in the diamonds below: 2-84. See below: (3.5, 0) and (0, –2.33) = 4.33 y ≈ 2-85. See below: 3, (0, 5) , (0, 0) 0, (0, 3) 4, (0, 7) 2-86. See graph below:
The slope is 5.2, so y = 5.2x + b. The y-intercept is still unknown. Possible response: A point on a line is a solution to the equation, so when substituting the x- and y-values into the equation, the equation is still true. Substituting y = 9 and y = 98.4 into the equation, the equation becomes 98.4 = 5.2(9) + b. After solving, b = 51.6 and y = 5.2x + 51.6. The equation is exact and the units for the y-intercept are grams. Starting with 140 = 5.2x + 51.6, the solution becomes x = 17 days. 2-79. See below: y = –3x – 5 y = 0.5x – 14 2-80. Mt. Everest was 8750.05 meters tall in the year 0; y = 0.05x + 8750.05. The units for m are years and for b are meters. The answer should be carried to the hundredths place because 5 cm is .05 m. 2-81. See Suggested Lesson Activity for possible answers. 2-82. See below: y = 1.5x + 0.5 Answers vary, but solutions should lie on y = 1.5x + 0.5. Possible points: (0, 0.5), (1, 2), (10, 15.5) 2-83. Find solutions in bold in the diamonds below: 2-84. See below: (3.5, 0) and (0, –2.33) y = ≈ 4.33 2-85. See below: 3, (0, 5) , (0, 0) 0, (0, 3) 4, (0, 7) 2-86. See graph below: