Aparticular chemistry book costs $6 less than a particular physics book, while two such chemistry books and three such physics books cost a total of $123. construct two simultaneous equations and solve them using substitution method.

Hello!

Set two variables for this situation. Let c = the cost of the chemistry book, and p = the cost of the physics book.

Create equations for the two statements seen here.

A chemistry book costs $6 less than a particular physics book: c + 6 = p

Two chemistry books and three physics book equal $123: 2c + 3p = 123

Now, set up your system of equations.

To solve, you're looking to use the substitution method. This method first takes an equation, and solves for a certain variable with it, and then substitutes in the equation for that certain variable into the other equation. That explanation was confusing, but hopefully it gets clearer here:

Since c + 6 = p, substitute c + 6 into the other equation for p.

2c + 3p = 123

2c + 3(c + 6) = 123

And now solve for c.

2c + 3(c + 6) = 123

2c + 3c + 18 = 123

5c = 105

c = 21

To find the other variable, just substitute c in one of the original equations.

c + 6 = p

21 + 6 = p

p = 27

Therefore, you have your solution. The chemistry book costs $21, and the physics book costs $27.

Hope this helps!

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

c) the median for town a 30" is greater than the median for town b 25"

step-by-step explanation:

town a, median = q2 = 30

town b, median - q2 = 25

so the median for town a 30" is greater than the median for town b 25"