Mental math is something that can be done i your head.
for example you can do 1+1 in your head and you dont need a calculator or paper to do it so i would be called mental math
Hope this helps
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I believe it would be 1.5 cm squared because 7.5/5 = 5
Answer:
13 is two and two thirds of four and seven eighths.
Step-by-step explanation:
To solve this, all you need to do is divide 13 by 2 and two thirds. Let's do it:

We have that
<span>4x -2y =22------> clear variable y
2y=4x-22--------> y=4x/2-22/2---------> y=2x-11-----> equation 1
2x + 4y = 6------> equation 2
substitute equation 1 in equation 2
2x+4*[2x-11]=6-----> 2x+8x-44=6----> 10x=50------> x=5
then
y=2x-11----> y=2*5-11----> y=-1
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