1. The correct statement is the first one, which is: <span>Add the two equations, solve for y, and then substitute –1 for y to find x.
</span>
2. Therefore, you have the following system of equations:
<span>
4x+8y=20
-4x+2y= -30
3. When you a</span>dd the two equations, and clear the variable "y", you obtain:
10y=-10
y=-1
4. Now, you must substitute -1 for y (y=-1) to find x, as below:
4x+8y=20
4x+8(-1)=20
4x-8=20
4x=20+8
4x=28
x=28/4
x=7
BEST estimate of this amount is
. Correct option A. 2 x 10^7 .
<u>Step-by-step explanation:</u>
Here we have , Hoover Dam spans the Colorado River on the Nevada-Arizona state line. For its construction, the federal government purchased 21,670,000 pounds of gates and valves. We need to find BEST estimate of this amount . Let's find out:
21,670,000 pounds
⇒ 21,670,000 pounds
⇒ 
⇒ 
⇒ 
⇒ 
⇒ 
Now, Rounding of 2.167 we get 2 ,So
⇒ 
Hence , BEST estimate of this amount is
. Correct option A. 2 x 10^7 .
Answer:
put the examples on the test or assignment so i can answer it
Answer: 1 1/5
Step-by-step explanation: I dont really have an explanation...