Answer:
-4
Step-by-step explanation:
10y+50=10
10y=-40
y=-4
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
or 
Part b) the oldest age Martin's sister can be is
years old
This will be a 4th quadrant 3,4,5 triangle.
Sin = -3/5
Tan = -3/4
Setup: cos48 = x/25
25(cos48) = x
x = <span>16.728265159</span>
X³ + 216 = 0
x³ = 0 - 216
x³ = - 216 Take the cube root of both sides.
∛x³ = ∛-216
x = -6
Check:
x³ + 216 = 0, x = -6
(-6)³ + 216 = 0
-216 + 216 = 0
0 = 0 Correct.