Imagine that you tied a string around the center of the Earth along the equator. The string lies on top of the ground and the oceans. You then untied the string and added 6 more meters to the string. You pulled the string away from all sides of the Earth equally. What is the largest animal that could crawl under the string?

A) ant B) mouse Explain your thinking. Write C) cat your choice on a sticky and D) goat give to Evidence Engineer to post. E) horse

Algebra 1

Solving for y & Identify Slope & Intercept

Lesson 4 A.CED.4, A.REI.3, A.REI.10, F.LE.1a

COPY THIS! Direct Variation y=kx Looks very similar to y = mx, so slope is also known

as the constant of variation (k). If a function varies directly, it is proportional and

can be solved with a proportion. Both variables also moves in the same direction or . For example, package weight and cost to mail or amount of gas and miles driven.1) If y varies directly with x, and y = 18 when x=12, what is the value of y when x = 5?2) A recipe for a dozen corn muffins calls for

1 cup of flour. The number of muffins varies directly with the amount of flour. How many cups of flour are needed for 65 muffins?

Use post-its to write statements that either compare (same) or contrast

(different) EQUATIONS AND INEQUALITIES

PLACE THEM ON THE CHART PAPER IN FRONT.

Vocabulary – Do you remember?

Slope-Intercept Form: y = mx + b slope y-intercept “movement” “beginning”

Can you hear the “m” and “b”?A cell phone company charges $.05 per text and a

base rate of $10 each month. Write an equation to model your monthly bill.

Examples. Isolate y.

1) 2x + 5y = 8 2) 2x = 8 + y

Examples

3) -3x + 2y = 4 4) 5x – y = 8

Examples5) 6)

385

41 yx 24

1 32 xy

Slope-Intercept Form y=mx+b m = slope (rise/run) b = y-intercept (where line crosses y-

axis) y = -4x + 3 m=____b=____ y = -x – 7 m=____b=____ y = 3 + ¾x m=____b=____ y - 6 = ½x m=____b=____

m= -3 b= ¼ slope-int form:_____________

ExamplesFind the slope and y-intercept of each

equation.

7) y = -2x + 1 10) y = ½ x – 5

8) y = ⅝x 11) y = 5

9) 2x + 3y = 7 12) -3x – 2y = 14

Write an equation in slope-intercept form.

13) m = 3, b = 4 14) m = 0, b = -3

15) m = undefined, b = 4

m=movement b= beginning16) A cell phone company charges $.05 per

text and a base rate of $10 each month. Write an equation to model your monthly bill.

Examples

Write the equation of the line.17) 18)

Assignment

Why Did the Cow Want a Divorce?