5. SEP Use Mathematics The mass of an isotope can be approximated by adding together the number of protons and neutrons in its nucleus. For example, a
carbon-12 nucleus has 6 protons and 6 neutrons, and its mass is approximately
12 amu. Look at the models for the two isotopes of boron. Each model shows the
isotope's natural percent abundance and the composition of its nucleus. Use the
data to calculate the approximate atomic mass of boron.
Spº
6n
2092
8092

linda: 3 ; laura: 15

step-by-step explanation:

note that linda + laura's age is 18, and that linda is 12 years younger than her sister.

let "linda" = x , "laura" = y:

x + y = 18

x = y - 12

first, plug in y - 12 for x in the first equation:

(y - 12) + y = 18

simplify.

2y - 12 = 18

isolate the variable (y). note the equal sign, what you do to one side, you do to the other. do the opposite of pemdas. first add, then divide.

2y - 12 (+12) = 18 (+12)

2y = 18 + 12

2y = 30

(2y)/2 = (30)/2

y = 30/2

y = 15

next, plug in 15 for y in the second equation (the other equation would work too).

x = y - 12

x = (15) - 12

x = 3

linda's age is 3, laura's age is 15.

~

i think its 100

i hope this !