If x+y=15 and x-y=25, then what is the value of 2x^2 - y^2?

775

Step-by-step explanation:

We are given two equations in which we can perform systems of equations by putting these two equations on top of each other then solving for one variable:

x+y=15

x-y=25

Here, we can cancel out the y variable and get:

2x=40

x=20

Then we can put the x variable into any of the equations to solve for y (in this case I will use the equation x+y=15 so 20+y=15

y=-5

Now, we can solve by plugging both variables into 2x^2 - y^2 :

2(20)^2 - (-5)^2

800-25 = 775

I hope this helps!

775

Step-by-step explanation:

Hi there!

We are given the following system of equations:

x+y=15

x-y=25

and we need to find the value of 2x²-y²

First, let's find the value of x and y

Let's add the 2 equations together to clear y and solve for x (y-y=0)

2x=40

divide both sides by 2

x=20

Now substitute 20 as x into either one of the equations to solve for y

To do x-y=25 for instance,

20-y=25

subtract 20 from both sides

-y=5

multiply both sides by -1

y=-5

Now we know that x=20 and y=-5

Substitute those values into the expression (remember: y² is equal to y×y, or (y)²)

2(20)²-(-5)²

Raise to the second power

2(400)-(25)

multiply and open parenthesis

800-25

subtract

775

Hope this helps!

ok

step-by-step explanation:

the correct functions are

h(x) = 3x + 2  

g(x) = 2^x

step-by-step explanation:

i proceed to calculate the different values ​​of k (x)

case 1)  k(x) = g(x) ∘ h(x)

g(x) ∘ h(x)=g(h(x))

k(x) = [2]^[3x + > is the option  4. k(x) = 2^(3x + 2 )

case 2)  k(x) = g(x) + h(x)

k(x) = [2^x]+[3x + 2]=2^x+3x+> is the option  1.) k(x) = 2^x + 3x + 2

case 3)k(x) = h(x) ÷ g(x)

k(x) =  [3x + 2]/[2^x]=3x/(2^x)+2/(2^x)=3x*(2^-x)+2^(1-x)

is the option  3.)   k(x) = (3x)2^(-x) + 2^(-x + 1 )

case 4)k(x) = g(x) - h(x)

k(x) =  [2^x]-[3x + 2]=2^x-3x-> is the option  2.) k(x) = 2^x - 3x - 2 

case 5)  k(x) = g(x) × h(x)

k(x) = [2^x]*[3x + > is the option  5.) k(x) = 2^x(3x + 2)

case 6)k(x) = h(x) ∘ g(x)

h(x) ∘ g(x)=h(g(x))

k(x)=3*[2^x]+> is the option  6. k(x) = 3(2^x) +2