Answer:
C. 2 times as long
Step-by-step explanation
8 times 10^-7 written in standard form is 0.0000008
4 times 10^-7 written in standard form is 0.0000004
divide both of them:
=2
Elimination:
7x - 3y = 20
5x + 3y = 16
(add)
12x = 36
÷ 12
x = 3
(5 × 3) + 3y = 16
15 + 3y = 16
- 15
3y = 1
÷ 3
y = 1/3
Substitution:
5x + 3y = 16
- 3y
5x = 16 - 3y
÷ 5
x = 3.2 - 0.6y
5(3.2 - 0.6y) + 3y = 16
16 - 3y + 3y = 16
16 = 16
- 16
6y = 0
÷ 6
y = 0
Sorry the substitution messed up for some reason, I'll fix it after I've answered the other question
First convert 7.5 meters to 750cm, then use your formula A=1/2bh and pop it in your calculator: (1/2)(750)(6) and be sure to include cm as the unit of measurement in your final answer.
11) 7 + -10+(4(5+-3)) = 7+-10+8=5
12) (12 +-10)+3x+-1(2x+4x), 12+-10x+3x+-2x+-4x = 12+-13x