If it is a punchline the answer would be elepants.
If not a punchline animals can keep themselves warm with thick skin or feathers.

Solve the following using Substitution method
2x – 5y = -13
3x + 4y = 15


- To solve a pair of equations using substitution, first solve one of the equations for one of the variables. Then substitute the result for that variable in the other equation.

- Choose one of the equations and solve it for x by isolating x on the left-hand side of the equal sign. I'm choosing the 1st equation for now.

- Add 5y to both sides of the equation.


- Multiply
times 5y - 13.

- Substitute
for x in the other equation, 3x + 4y = 15.

- Multiply 3 times
.

- Add
to 4y.

- Add
to both sides of the equation.

- Divide both sides of the equation by 23/2, which is the same as multiplying both sides by the reciprocal of the fraction.

- Substitute 3 for y in
. Because the resulting equation contains only one variable, you can solve for x directly.


- Add
to
by finding a common denominator and adding the numerators. Then reduce the fraction to its lowest terms if possible.

- The system is now solved. The value of x & y will be 1 & 3 respectively.

Answer:
$2.7
Step-by-step explanation:
Let the price of one apple be x
and the price of one orange y
Hence ;
One apple and 3 oranges would cost:
x + 3×y = $5.10----------------------------(1)
One apple and 5 oranges would cost;
x + 5×y = $7.50--------------------------(2)
Subtracting eqn (1) from (2), we have :
x-x + 5y -3y = 7.5- 5.1
2y = 2.4
y = $1.2
From eqn(1)
x + 3y = $5.10
x= $5.10-3($1.2) = $5.10-$3.6 = $1.5
Hence x=$1.5 and y= $1.2
We are required to find the cost of one apple and one orange, hence :
x+y = $1.5+$1.2= $2.7
So first let’s combine like terms and add 4/9x and 1/5x together to get 29/45x =58. Next, multiply 58 by 45/29 to isolate x, so x=90