Download Use Square Roots to Solve Quadratic Equations (10.4)

Use Square Roots to Solve
Quadratic Equations (4.5 and 6)
December
nd
2
Use Square Roots to Solve Quadratics
 Goal: get x2 alone on one side of the equation. Then you’ll
be able square root each side to find x.
 Remember: when you take the square root of a number,
your solution will have a positive version and a negative
version. We can abbreviate this with the sign: ±
2x2 = 8
x2 = 4
x = ± √4
x= ±2
(check your answer by putting the answers into the original equation)
Use Square Roots to Solve Quadratics
m2 – 18 = -18
+ 18 + 18
m2 = 0
m = ± √0
m=0
Use Square Roots to Solve Quadratics
b2 + 12 = 5
-12 -12
b2 = -7
b = ± √-7
imaginary
 To take the square root of a negative number will
give you an “imaginary” solution. Your calculator
will say error, but DON’T write down no solution.
Do it like we did yesterday.
Use Square Roots to Solve Quadratics
9p2 – 35 = 14
Use Square Roots to Solve Quadratics
4z2 = 9
Use Square Roots to Solve Quadratics
3x2 – 11 = 7
+11 +11
3x2 = 18
x2 = 6
x = ± √6
Use Square Roots to Solve Quadratics
6(x – 4)2 = 42
(x – 4)2 = 7
x – 4 = ± √7
+ 4 +4
Use Square Roots to Solve Quadratics
3(t + 5)2 = 24
(t + 5)2 = 8
t + 5 = ± √8
- 5 -5
Homework
 worksheet
 QUIZ NEXT TIME