
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:

Step-by-step explanation:
For
the set of points that include all solutions are
such that
; then we have
.
What is important to stress here is that
represents all of the solutions, while other points that we are given represent one solution (for example, point (2,-1) is just one solution)
Answer:
free throws = 6
2 points shots = 3
Step-by-step explanation:
To do this we will have 2 incognitas.
x = number of free throws
y = number of shots of 2 points
x(1) + y(2) = 12
he says he made twice as many free throws as 2 points
x = 2y
2y(1) + y(2) = 12
2y + 2y = 12
4y = 12
y = 12/4
y = 3
x = 2y
x = 2*3
x = 6
free throws = 6
2 points shots = 3
1.) You have 12 toppings. You choose one topping--that leaves you with 11 toppings. You choose another--that leaves 10. 12×11×10 = 1,320.
Multiply 1,320 topping choices by 6 cheeses to get 7,920 total combinations.
2.) (Though I'm less sure of these)
CDs: 6×5×4×3×2 = 720
Cassettes: 5×4 = 20
DVDs: 8×7×6×5 = 1680
70℅ = 14
100 = X
70X = 1400
X = 1400/70
X = 20
20 Euros is the full price