You need a 30% alcohol solution. on hand, you have a 90 ml of a 45% alcohol mixture. how much pure water will you need to add to obtain the desired solution?
you will need
ml of pure water
to obtain
ml of the desired 30% solution.

45ml of pure water to obtain 135ml of the desired 30% solution

Step-by-step explanation:

45% of 90 = 40.5

So, 40.5ml of alcohol in 90ml

We want 30% and therefore need a ratio of 3:7

40.5÷3=13.5

so one part of our ratio is 13.5

we then times this by 7

13.5 x 7 = 94.5

so, 94.5ml of water

to work out how much we already have, we should do 90ml- 40.5ml = 49.5ml

and then 94.5- 49.5 = 45ml

We need 45ml of water and the total mo of the desired solution will be 90+45=135ml

x= -3 and

step-by-step explanation:

to find the roots of a cubic, use division or factoring to find the factors then set equal to 0. as this is a difference of cubes, it factors into

where a is the cube root of .

here   this is 27 and the cube root of 27 is 3. so we write using the form:

.

set each factor to 0 and solve for x.

x-3=0

x=3

the quadratic expression does not factor and must be solved using the quadratic formula.

where a = 1, b=3, and c=9

this cubic has two complex roots.

me! what did you put for this question?

step-by-step explanation: