1. 9.1 Solving quadratic equations using square roots
Goal:
Solve a quadratic equation by finding square roots.
Eligible Content: A

2. Vocabulary
Square Root – a number that, when multiplied by itself, will result in a given number.
Radical Symbol – the symbol used to represent the square root of a number
Radicand – the number under the square root symbol
Perfect Square – numbers whose square roots are integers or quotients of integers.

3. Vocabulary
Quadratic Equation – any equation whose largest exponent is 2.
Examples:

4. Vocabulary Solution – any number that works in the equation.
Most quadratic equations have 2 solutions!

5. Solve for x:

6. Examples x2 = 4 4x2 = 64 x2 + 9 = 90 3x2 – 48 = 0 2x2 + 5 = -13
x = 2 and x = -2
x = 4 and x = -4
x = 9 and x = -9
x = 4 and -4
No solution
x ≈ 1.41 and x ≈ -1.41
x ≈ 3.74 and x ≈ -3.74

7. Practice Solve each quadratic equation: 2x2 – 12 = 116 4x2 + 6 = 42
ANSWERS:
x = 8, -8
x = 3, -3
x = 10, -10
x ≈ 3.87, -3.87
Not possible

8. Homework
Worksheet – “Solving Quadratic Equations with Square Roots”