Answer:
4L + 8H = 512 (First answer)
You can take 92 low resolution pictures (second answer)
Explanation:
Let L represent the number of low resolution pictures you take and H the number of high resolution pictures you can take.
You only have 512 megabytes.
Therefore, the number of megabytes the low resolution pictures you take plus the amount of megabytes the high rsolution you take in total should be 512
Therefore your equation is:
4L + 8H = 512 (First answer)
You took 18 high resolution pictures, so substitute 18 for H
4L+8(18) = 512
4L+144=512
subtract 144 on both sides
4L=368
divide by 4
L= 92
You can take 92 low resolution pictures
Hope this helps!