18h+4b-2b
8 h 30 min =7h 100 m 7h 100min-4h 55 min=3h 45 min
Unless you have a value for 'h', the answer will just be an expression: 10 + 7h
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(7h + 35) / (-7) = (7h)/(-7) + (35)/(-7) = (-h) + (-5) = - (h + 5)
If: 7h+4 = -80 then h = -12
8 h 30 min =7h 100 m 7h 100min-4h 55 min=3h 45 min
4h + 7h - 16 = 6 Combine like terms: 11h - 16 = 6 Add 16 to both sides: 11h = 22 Divide both sides by 11: h = 2
Unless you have a value for 'h', the answer will just be an expression: 10 + 7h
7h - 2 - 51 is an expression NOT an equation. An expression cannot be solved for the value of a variable.
It is: 11h
The order of hardness goes:9H 8H 7H 6H 5H 4H 3H 2H H F HB B 2B 3B 4B 5B 6B 7B 8B 9B hard medium soft
According to wikipedia hydrogen has three naturally occuring isotopes, 1H, 2H and 3H. 4H through 7H have been created in the laboratory but they are very short-lived.
here is a web site with a page on pencils www.easydrawinglessons.com
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In order, the leads are (from softest to hardest): 9B/8B/7B/6B/5B/4B/3B/2B/B/HB/F/H/2H/3H/4H/5H/6H/7H/8H/9H HB is the most commonly used lead for general purposes. The softer leads are used for art drawing, the harder for fine ledger work.
H stands for hardness and B stands for blackness this is how a pencil scale goes: 9H 8H 7H 6H 5H 4H 3H 2H 1H H HB B 1B 2B 3B 4B 5B 6B 7B 8B 9B9H is very fine hard and light but 9B is thick black and very soft (more like charcoal)
Pencils are all marked on a European system called the degree scale where H is hardest and B is blackest.Pencils can be marked as;9H, 8H, 7H, 6H, 5H, 4H,3H,2H, H F,HB, B, 2B, 3B, 4B ,5B ,6B ,7B ,8B ,9BH pencils have a higher concentrate of clay than graphite, whereas the B pencils have a much lower percentage of clay.The B pencils make soft, dark marks, whereas the H pencils have a much harder, lighter mark.The F pencil stands for fine point, which is slightly harder than the HB making it a good writingpencil.