01 – What is algebra?
What is Algebra:
The word “Algebra” comes from the Arabic word Al-Jabr in the title of a book, Hidab al-jabr wal-muqubala, written in Baghdad about 825 A.D. by the Arab mathematician Mohammed ibn-Musa al-Khowarizmi.
The title has been translated to mean “science of restoration (or reunion) and opposition” or “science of transposition and cancellation” and “The Book of Completion and Cancellation”.
Algebra is used to find the missing number in ☐ – 6 = 10. But rather than use ☐, algebra uses letters for unknowns, so we write x – 6 = 10
To solve the equation, the left-side, where x is lessened by 6, is “restored” or “completed” back to x. To do this we add 6. But we also must add 6 to the right for completeness, so x = 16
If we write x + 2 = 3 then we ask how do we restore the left side to x.
We subtract 2. But we must also take 2 from the right for completeness. So x = 1.
x is the unknown and it equals 1.
The process to work this out is to imagine a balance with x + 2 on the left and 3 on the right. If we remove the 2 from the left the balance tilts. If we also take off 2 from the right, giving 1, the balance is restored with x on the left and 1 on the right. So x = 1
In y + 6 = 10 . What value does y have?