Algebra

Algebra 1 STAAR Retest Lesson

System of Equations

Solving systems of equations

• Graphing

• Elimination

• Substitution

Solving systems of equations by graphing is the best way!

• Step 1: Convert standard form linear equations to slope-intercept form

• Graph both equations in your calculator

• Find the point of intersection

Converting Standard Form to Slope Intercept Form

• Since your calculators are in press-to-test mode you cannot graph a linear function in standard form, Ax+By=C.

• You need to convert standard form, Ax+By=C, into slope intercept form, y=mx+b

Converting Standard Form to Slope Intercept Form: Ax+By=C >> y=mx+b

• Step 1: Move Ax by adding or subtracting

• Step 2: Divide both sides by B

• Step 3: Simplify

• Step 4: Write in slope intercept form

Multiple Choice

Convert 4x+2y=10 into slope intercept form

• y=-2x-5

• y=3x

• y=5-4x

• y=10-2x

Multiple Choice

Convert x-y=4

• y=-x+4

• -y=-x+4

• x=y+4

• y=x-4

Linear/Exponential/Quadratic Regression

Linear/Exponential/Quadratic Regression

Regression is when you plug into your calculator a table of data and then generate a line of best fit for the data

Linear Regression Steps:

• New Document

• Add Lists and Spreadsheets

• Click Menu-4-1-3

• Enter 'x and 'y

• m is slope b is the y intercept

• y = mx+b is your equation

Exponential Regression Steps:

• New Document

• Add Lists and Spreadsheets

• Enter 'x and 'y

• Fill out the table with the data provided

• Click Menu-4-1-A

• a is Initial Amount b is the Factor

• y= a(b^x) is the equation

Quadratic Regression Steps:

• New Document

• Add Lists and Spreadsheets

• Enter 'x and 'y

• Fill out the table with the data provided

• Click Menu-4-1-6

• y=ax²+bx+c is your equation

• Use a, b, and c from the calculator

Multiple Choice

Which equation best represents the linear data shown?

• y=5x-2

• y=-2x+5

Multiple Choice

Which equation best represents the exponential data shown?

• y=3(2^x)

• y=2(3^x)

Multiple Choice

Which equation best represents the quadrtic data shown?

• y=-x²+3x-12

• y=-12x²-x+3

• y=3x²-12x-1

• y=3x²-x-12