Answer:

195 mL of the 90% solution

Step-by-step explanation:

Let the number of mL of 90% mixture = x

Hence, our equation is

780mL × 15% + x mL × 90% = (780mL + x) 30%

117 + 0.9x = 234 + 0.3x

Collect like terms

0.9x - 0.3x = 234 - 117

0.6x = 117

x = 117/0.6

x = 195 mL

Therefore, You will need 195 mL of the 90% solution

<em><u>**Complete Question:**</u></em>

The equation a= 180(n-2)/n represents the angle measures, a, in a regular n-sided polygon. When the equation is solved for n, n is equal to a fraction with a denominator of a – 180. What is the numerator of the fraction?

<em><u>**Answer:**</u></em>

**The numerator of fraction is -360**

<em><u>**Solution:**</u></em>

Given that,

<em><u>**The equation represents the angle measures, a, in a regular n-sided polygon is:**</u></em>

We have to solve the equation for "n"

Rearrange the equation

Thus the numerator of the fraction is -360

The correct option is (2)

For any quadratic equation: ax2 + bx + c = 0.

The complex roots are expressed in the form a ± bi.

where a is the real part

& b is the imaginary part.

Since, one root is √7 + 5i, therefore the other root will be of the form <span>√7 - 5i.

Hence, option (2) is correct.</span>

The answer is C because when it reflects the 4 stays negative and the 6 because negative because it reflected on the negative side

Hope this helped! :))

**Answer:**

A C E

**Step-by-step explanation:**

pls mark brainliest