the example of an open equation is :x+9=16
Step-by-step explanation:
Since, y varies directly as x:
![\therefore \: y = kx..(1) \\ (k = constant \: of \: proportionality) \\ at \: y = 21 \: and \: x = 7 \\ 21 = k \times 7 \\ k = \frac{21}{7} = 3 \\ plugging \: k = 3 \: in \: equation \: (1) \\ y = 3x..(2) \\ plugging \: \: y = - 5 \: in \: (2)\\ - 5 = 3x \\ x = \frac{ - 5}{3} \\ \: \: \: \: \: \: \huge \red{ \boxed{x = - \frac{5}{3} }}](https://tex.z-dn.net/?f=%20%5Ctherefore%20%5C%3A%20y%20%3D%20kx..%281%29%20%5C%5C%20%28k%20%3D%20constant%20%5C%3A%20of%20%5C%3A%20proportionality%29%20%5C%5C%20at%20%5C%3A%20y%20%3D%2021%20%5C%3A%20and%20%5C%3A%20x%20%3D%207%20%5C%5C%2021%20%3D%20k%20%5Ctimes%207%20%5C%5C%20k%20%3D%20%20%5Cfrac%7B21%7D%7B7%7D%20%20%3D%203%20%5C%5C%20plugging%20%5C%3A%20k%20%3D%203%20%5C%3A%20in%20%5C%3A%20equation%20%5C%3A%20%281%29%20%5C%5C%20y%20%3D%203x..%282%29%20%5C%5C%20plugging%20%5C%3A%20%20%5C%3A%20y%20%3D%20%20-%205%20%20%5C%3A%20in%20%5C%3A%20%282%29%5C%5C%20%20-%205%20%3D%203x%20%5C%5C%20x%20%3D%20%20%5Cfrac%7B%20-%205%7D%7B3%7D%20%20%5C%5C%20%20%20%5C%3A%20%20%5C%3A%20%20%5C%3A%20%20%5C%3A%20%20%5C%3A%20%20%5C%3A%20%5Chuge%20%5Cred%7B%20%5Cboxed%7Bx%20%3D%20%20-%20%20%5Cfrac%7B5%7D%7B3%7D%20%7D%7D)
The correct match of each tile of the equation with its solution is:
- n - 13 = - 12 →→→ 1
- n/5 = -1/5 →→→ -1
- n + 15 = - 10 →→→ -25
<h3>How do we match each tile to the correct box?</h3>
To match each tile to the correct box, we have to solve the arithmetic operations in the box, then drag the correct tile that matches our answer into the box.
From the image attached below;
1.
n - 13 = - 12
Let us add (+13) to both sides to eliminate (-13), i.e.
n - 13 + 13 = - 12 + 13
n = 1
2.
n/5 = -1/5
multiply both side by 5
n/5 × (5) = -1/5 × (5)
n = -1
3.
n + 15 = - 10
n +15 - 15 = - 10 - 15
n = -25
Learn more about matching each tile to the correct box here:
brainly.com/question/17203448
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Answer: x= -2
Step-by-step explanation: