Answer:
if d=dogs and c=cats then c+20=d
Step-by-step explanation:
Hello! Haley has 7 pens, with 3 more of them being blue than black. If you do some mental math, you know that 5 is 3 more than 2 and 2 + 5 is 7. So Haley has 5 blue pens and 2 black pens.
3x+9=6x
-9 -9
—————
3x=6x-9
-6x -6x
—————
3x-6x=-9
-3x=-9
x=3
hope it helped