352 alGEbra De mystif ieD

Solve the equation by factoring.

39 xx^2 −− 30 = 0

39 xx^22 −− 30 =− 03 becomes3()xx−= 10 0 whichbecomes3(()xx()

xx

x

−+=

−= +=

++ −−

520

50 20

55 22

.

=== 52 x −

We do not set the factor 3 equal to zero because “3 = 0” does not lead to a

solution.

PRACTICE

Solve the equation by factoring.

1. xx^2 −− = 12 0


2. xx^2 ++ 7120 =


3. xx^2 +=− 815


4. xx^2 −=− 10 21


5. 32 xx^2 −−= 0


6. 48 xx^2 −= 5


7. x^2 −= 25 0


8. 91 x^2 −= 60


9. x^2 = 100


10. xx^2 ++= 690


11. x^2 = 0


12. 50 x^2 =


13. x^21
    9

−= 0

✔SOLUTIONS

1. xx
   xx
   xx

x

(^2120)
430
40 30
44 33
4
−− =
−+=
−= +=
++ −−

()()
xx=−  3
PRACTICE
Solve the equation by factoring.

1. xx

PRACTICE

Solve the equation by factoring.