Mr. Fahrenbacher/Mr. Baumstark Algebra 22 – Solve by Undo / Day 2

Name:_________________________

Example 1: Sketch the graph of the following two quadratic equations and find the x – intercepts of each. y=−x 2+5

y=−( x−4)2+5

x

x

y

y

Using solve by undo: Find x-intercepts of

Example 2: Solve

y=−x 2+5

2

3( x−5) −9=0

Find x-intercepts of

Example 3: Solve

y=−( x−4)2+5

( x+2)2+10=0

Practice 1. Solve the following equations for x a)

(x−5)2=81

b)

48=14+2( x +3) 2

c)

4 ( x+2)2=20

d)

3( x−1)2 +4=19

e) −( x+6) 2−3=−33

f)

2. Find the x-intercepts of the quadratic equation

(x+7)2 +17=0

y=−2( x+3)2+16

3. Baseball. After a baseball is hit, the height h (in feet) of the ball above the ground t seconds after it is hit can be approximated by the equation h=−16(t−2)2 +67 . Determine how long it will take the ball to hit the ground. [Hint: what is the height when the ball hits the ground?]