(f-g)(x) = x²+6x - (7-x)
(f-g)(x) = x² + 6x - 7 + x
(f-g)(x) = x² + 7x - 7
(f-g)(9) = 9² + 7*9 - 7
(f-g)(9) = 81 + 63 - 7
(f-g)(9) = 137
Step-by-step explanation:
1. x: (-12, -13) y: (12, 13)
2. x: (4 ,9) y: (-4, -9)
3. x: (-10, 8) y: (10, -8)
Let x be the amount of cement and y be the amount of sand. If <span>the ratio of cement to sand for mortar is 1:3, then

and y=3x.
</span>
So, if <span>Sandy puts in x=7 shovels of cement, then she puts

shovels of sand.
</span><span>
</span><span>
Answer: 21 shovels of sand.
</span>
(X+12) + 140 = 180
X + 12 + 140 = 180
X + 152 = 180
X = 180 - 152
X = 28
Triangle B can be proven congruent