Answer:
2x + y = 12 x = 9 − 2y x + 2y = 9 2x + 4y = 20 x + 3y = 16 2x − y = 11 y = 11 − 2x 4x − 3y = -13 y = 10 + x -3x + 3y = 30 2x + y = 11 x − 2y = -7 x = 2, y = 7 arrowRight x = 5, y = 2 arrowRight x = 3, y = 5 arrowRight x = 7, y = 6
Step-by-step explanation:
4th
I don’t see the image can u re- upload it
Let
x---------> represents Martin's sister's age
y--------> represents Martin's age
we know that
--------> equation 
--------> equation 
Substitute equation in equation
![x+[x-6]\leq 22\\2x\leq 22+6\\ x\leq 14](https://tex.z-dn.net/?f=%20x%2B%5Bx-6%5D%5Cleq%2022%5C%5C2x%5Cleq%2022%2B6%5C%5C%20x%5Cleq%2014)
therefore
<u>the answer is</u>
Part a) An inequality that can be used to represent this situation is
![x+[x-6]\leq 22](https://tex.z-dn.net/?f=%20x%2B%5Bx-6%5D%5Cleq%2022%20)
or 
Part b) the oldest age Martin's sister can be is 
years old
No intervals are showing, but here is how to solve this equation.
0.35x - 4.8 < 5.2 - 0.9x
Add 4.8 to both sides
0.35x < 10 - 0.9x
add 0.9x to both sides
1.25x < 10
divide both sides by 1.25
x < 8
Interval Notation:
If we graphed this on a number line, x goes toward negative infinity.
Answer: (-∞, 8)
Hope this helps! :)
The x-axis is usually the horizontal axis, while the y-axis is the vertical axis. They are represented by two number lines that intersect perpendicularly at the origin, located at (0, 0), as shown in the figure below.
