Jumpstart your brain! 5 Questions – 5 points You have 1 minute per question. Good luck.

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Show the work! 1)The slope of the line through (5,-4) and (5,-10) is … a) positive b) negative c) zero d) undefined

Show the work! 2)The slope of the line passing through (a,b) and (c,d) is … a) b) c)d)

Show the work! 3) Which equation best describes the graph? a) y=2x b) y=-2x c) d)

Show the work! 4) Which equation does NOT model a direct variation? a) y=4xb)y=22x c)y=3x+1d)

Show the work! 5) Evaluate -2x-7y if x=-5 and y=-4… a) 38b)43 c)227d)243

TIMES UP… Get ready to check your answers READY SET GO!

Answers: Check it. Circle the number you got right. 1) D 2) B 3) D 4) C 5) A

Chapter Analyzing Linear Equations

5.3 Slope-Intercept Form The slope-intercept form looks like this… slope= rise over run Y-intercept  where the line crosses the y-axis

Write a slope-intercept equation Step 1) Find m Step 2) Find b Step 3) Plug the values for m and b into y=mx+b ***When you are done, the only variables left will be x and y

Example: Write a SI equation Write an equation (in slope-intercept form) for the line with slope 3 and y-intercept -2 y=mx+bSlope-intercept form Substitute m and b Simplify y=3x+-2 y=3x-2 Step 1) Find m Step 2) Find b Step 3) Plug in m and b

Write a slope-intercept equation Write an equation (in slope-intercept form) for the line shown. Slope formula Substitute (0,3) and (2,-1) Simplify Step 1) find m

Write a slope-intercept equation Write an equation (in slope-intercept form) for the line shown. Step 2) find b Slope-Intercept form b=3 Substitute m, b y=mx+b y=-2x+3 Step 3) plug in m & b

Graph a Slope-Intercept Equation Step 1) Plot b Step 2) From b, rise and run Step 3) Connect

Graph a Slope-Intercept equation… Graph Step 1) Plot b Step 2) From b, rise and run Step 3) Connect

Graph an equation in standard form… Graph BEFORE YOU CAN BEGIN>>>Put in SI form This means SOLVE FOR Y Original equation Subtract 5x Divide by -3 Simplify

Graph an equation in standard form… Step 1) Plot b Step 2) From b, rise and run Ok, now we have Step 3) Connect

Example: Write a SI equation Write an equation (in slope-intercept form) for the line through (1,5) with slope 2 y=mx+bSlope-intercept form Substitute 1, 5, and 2 Simplify 5=2(1)+b 5=2+b Step 1) Find m Step 2) Find b 5-2=b 3=b Subtract 2 Simplify

Example: Write a SI equation Write an equation (in slope-intercept form) for the line through (1,5) with slope 2 y=mx+bSlope-intercept form Substitute m and b y=2x+3 Now we know m=2 and b=3… Step 3) Plug in m and b

Example: Write a SI equation Write an equation (in slope-intercept form) for the line through (-3,-1) and (6,-4) Slope formula Substitute Step 1) Find m Simplify

Example: Write a SI equation Write an equation (in slope-intercept form) for the line through (-3,-1) and (6,-4) Slope Intercept Formula Substitute a point and m Simplify Step 2) Find b y=mx+b OK…now we know m= Subtract Simplify

Example: Write a SI equation Write an equation (in slope-intercept form) for the line through (-3,-1) and (6,-4) Slope Intercept Formula Substitute m and b Simplify Step 3) Plug in m and b y=mx+b OK…now we know m= and b=-2

Homework P : 17, 31-37odd P284: 11, 13, 19-23odd ALL ANSWERS ARE IN THE BOOK. YOU MUST SHOW THAT YOU CAN GET THE ANSWER ALGEBRAICALLY. If you get stuck try Username BHSHAWKS06