Find the x coordinate using -b/2a, then find the y coordinate. 1.) y = x2 + 4x - 2 2.) y = 2x2 - 4x - 4

y = 4 - 8 - 2 y = -6 Vertex = (-2,-6) 1.) y = x2 + 4x - 2

2.) y = 2x2 - 4x - 4 y = 2 - 4 - 4 y = -6 Vertex = (1,-6)

Today’s Objective To be able to solve a quadratic equation by using the quadratic formula.

Solving Equations with a radical Solve for x x2 = 81 x = 81 x =  9 Review

Solving Equations with a radical Solve for x x2 = 5 x = 5 x =  5 Review

The Quadratic Formula ax2 + bx + c = 0 x = -b b2 - 4ac 2a For equations of the form ax2 + bx + c = 0 x = -b b2 - 4ac 2a

Minus b, plus or minus the square root of b2 minus 4ac divided by 2a The Quadratic Formula Minus b, plus or minus the square root of b2 minus 4ac divided by 2a

The Quadratic Formula x = -b b2 - 4ac 2a

The Quadratic Formula y = ax2 +bx + c x2 -3x -18 = 0 x = -b b2 - 4ac 2a x = --3 (-3)2 - 4•1•(-18) 2•1

The Quadratic Formula x = --3 (-3)2 - 4•1•(-18) 2•1 x = 3 + 9 + 72=3+ 81 2 2 x =3 + 9 = 6 2 x =3 - 9 = -3 2

So The Solution is::: x2 -3x -18 = 0 x = 6 and -3

The Quadratic Formula y = ax2 +bx + c x2 - 9x + 18=0 x = -b b2 - 4ac 2a x = --9 (-9)2 - 4•1•18 2•1

The Quadratic Formula x = --9 (-9)2 - 4•1•18 2•1 x = 9 + 81 - 72=9+ 9 2 2 x =9 + 3 = 6 2 x =9 - 3 = 3 2

So The Solution is::: x2 -9x +18 = 0 x = 6 and 3

Now You Try First replace a,b,c in the formula x2 +3x -18 = 0 x = -b b2 - 4ac 2a

Now You Try First replace a,b,c in the formula x2 +3x -18 = 0 x = -3 32 - 4•1•(-18) 2•1

Now solve the formula x = -3 32 - 4•1•(-18) 2•1 x = -3 9 + 72 2

Now solve the formula x = -3 81 2 x = -3 9 2 x = 3, -6

Classwork Worksheet 9.4 Extra Practice (1-6) Homework page 475 (7-17)