Answer:
C. 
D. 
Step-by-step explanation:
C. 
D. 
Answer:
it's very blurry, and i can't see the question
Answer:
Roughly 18,000
Step-by-step explanation:
When you need to do rough mental math, you can do something like 720 vs 25 or 30 which is pretty simple to do in your head.
If you are very proficient in mental math, you can do something like 720 * 25, which is harder, but if you know the tricks, you can do this quickly.
720 * 25
Multiply 25 by 7.
175
Add two zeros.
17,500
Multiply 25 by 2
50
Add a zero.
500.
17500 + 500 = 18000
Hello,
Let's assume x the number
<h3>
Answer: True</h3>
Explanation:
Technically you could isolate any variable you wanted, from either equation. However, convention is to pick the variable in which isolating it is easiest, and most efficient.
The key thing to look for is if there's a coefficient of 1. This is found in the second equation for the y term. Think of -4x+y = -13 as -4x+1y = -13. Due to the coefficient of 1, when solving for y we won't involve messy fractions.
If you were to solve for y, then you'd get y = 4x-13, which is then plugged in (aka substituted) into the first equation. That allows you to solve for x. Once you know x, you can determine y.
