Answer:
It is not valid since there is more than one variable being changed at one.
Step-by-step explanation:
Jackson changed the brand of soil, but he also changes the amount of water, and the amount of sunlight the plants are receiving, so his conclusion that the soil was more effective is not valid.
Im assuming you mean 2x^2-3x-9=0 ?
If so, you have to factorise the equation
(2x-3) (x+3) = 0
2x - 3 = 0
2x = 3
x = 1.5
x + 3 = 0
x = -3
x is either 1.5 or -3
Multiply equation II by 2 and then add up the equations.
4.
4^3 = 64
64X64 = 4096
4^6 = 4096