Hint: Try using the Pythagorean thereom to solve it.
For Q3, you can subsitute x = 2 and y = 5 into the systems
-5(2) + 5 = -5
so it's a solution for the first system
-4(2)+2(5) = 2
it's also a solution for the second system
OK, a triangle first of all needs to have a certain condition satisfied. The length of one side of a triangle can not equal the length of 2 sides combined. So in a triangle a + b = c, a + b can not be less than c (a + b <span>≮ c</span>). Therefore, there are only a few possibilities that will work here. Let's find them:
16, 19, 43; no
16, 19, 50; no
16, 43, 50; yes
19, 43, 50; yes
Since only 2 out of 4 form triangles, there is a 50% chance you'll pick the right segments to form a triangle.
To calculate how much 9 apples cost, you must multiply 9 to 4.55 and then divide by 7. This is done by setting up a proportion.
