two coffees and four months and cause a total of $18 one coffee and three muffins cost a total of $11 what is the price of one muffin

$2

Step-by-step explanation:

Lets say coffee's are x, and muffins are y. We would rewrite it as 2x + 4y = 18, and x + 3y = 11.

You put those equations over each other:

2x + 4y = 18

x + 3y = 11

Multiply the whole bottom equation by 2, because then you can cancel the x's out. It would look like this:

2x + 4y = 18

2x + 6y = 22

Subtract the equations from each other, to get -2y = -4. Then divide -2 from both sides to get 2.

according to the triangle sum theorem, all the angles in a triangle must add up to 180 degrees. if we know one angle is already 90, we do 180-90=90. the other 2 angles must add up to 90, exactly.

step-by-step explanation: