Standard Form is ax + by = c, where a, b, and c are not fractions and a is not negative.
So, you can go through each of your options to see which ones work with those rules.
A. 2.5x + 3y = 12 No, this is not in Standard Form. 2.5 can be rewritten as 2<span>

, menaing A is a fraction, which you can't have.
B. -10x - 3y = 1 No, this is not in Standard Form. A is -10, but A can't be negative.
C. 2x + 3y = 12 Yes, this is in Standard Form. It follows all of the rules.
D. 5x + 5y = 10 Yes, this is in Standard Form. It follows all of the rules.
So,
C and
D are both written in Standard Form.
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Answer:
700 miles
Step-by-step explanation:
Given:
Scale of the map is 
∴ 
Distance of Susan from mount Shasha on the map is 7 inch.
Therefore, Number of miles = 
Hence, Susan must travel 700 miles to reach her destination.
Answer:
third quadrant
Step-by-step explanation:
if the coordinates are (-x,-y) it is located in the third quadrant
You're right - it's D. Both ratios are equal to 1/2.