Answer:
8 units by 10 units
Step-by-step explanation:

Answer:
option 2.
the others are simultaneous equations in two unknowns but 7x-2y have the same value and the value can't be two different things at once
Answer: 15.6 m
Step-by-step explanation:
Two legs of right angle in right triangle given are 12m and 10m.
For the third side use Pythagoras theorem:
C^2= a^2+b^2
C=√[(12^2)+(10^2)]
C=√[144+100]
C=√[244]= 15.6 m