Hello

1. Solve by factoring:
x2 – 9x = -20

x^2 -9x+20=0 Shifting 20 to left hand side

x^2 - 5x -4x +20 =0 Splitting 9x into 4x+5x

Taking x common from first two and -4 from other two

x(x-5) -4(x-5)=0

Taking x-5 common

(x-5)(x-4)=0

So either
x-5=0
or x=5

Else
x-4=0
x=4

Hope this helps

2. Solve using the square root property:
5x2 = 100

5x^2 = 100

x^2 = 100/ 5
x^2 = 20

x= +- sqrt (20)

3. Solve using the square root property:
(x + 2 = 81

Can you now try this your self?

4. Solve by completing the square:
x2 + 8x + 13 = 0

x^2 +2*4*x +13=0

x^2 +2*4*x + 13+3-3=0
x^2+2*4*x +16 - 3 =0
(x+4)^2 -3=0

x+4 = +-sqrt 3
x = sqrt 3 - 4
or x = -srt 3 -4

Hope this helps

5. Solve using the quadratic equation:
3x2 – 2x = 15x – 10

6. Solve using the quadratic equation:
x2 – 3x – 23 = 5

Try these and let me know if you have any problem