B - check your answers and present the solution
-7x-5y=-47x+9y=-4
combine like terms to cross out the 7x
solve for y, to get -2
plug it back in to one of the equations and x is 2
y=-2
x=2
3 triangles.
If you take 3 toothpicks you create the first triangle. You put the last toothpick down the middle, you get 2 more
You probably are interested in expressing the given equation as a quadratic equation in u, as it will make it easy to find the solutions.
Let u = x²
So,
u² = x⁴
So, the given equation can be written as:
u² - 17u + 16 = 0
Now the equation is quadratic in u and the solutions can be calculated using quadratic formula or factorization.
In order to get as many tickets they need 15 business class tickets and 12 economy class tickets (700x15=10,500)(375x12=4500) Which when you add those two makes 15,000.
