Please help me and give me an explanation

Hello!

Let's get important information in the exercise:

First, we need to know the total height (sum all students height). So, we can multiply the number of students by the mean height:

Now, we need to know the total height of the boys, likewise:

At this moment, we also need to know the total height of the girls. It's simple, just subtract:

Finally, calculating the mean height of the girls (just divide the total height by the number of girls):

So, the mean height of the girls equals 1.48.

Hope this helps! :)

-7

step-by-step explanation:

x^2 + 18x + 74 = (x + 9)^2 - 81 + 74

= (x + 9)^2 - 7.

so q = -7.

5/12, or 5: 12

step-by-step explanation: