X+2y=10
6x+6y=6 -> x+y=1
(x+2y=10)-(x+y=1)=y=9
x+(2*9)=10
x+18=10
x=-8 and y=9 -> c
Answer:
x = 
Step-by-step explanation:
Applying altitude- on - hypotenuse theorem.
(leg of large Δ )² = ( part of hypotenuse below it ) × ( whole hypotenuse )
x² = 3 × (3 + 7) = 3 × 10 = 30 ( take square root of both sides )
x = 
If I read it right then 1. -147
2. -100