solve({a+b=4,a-2*b=1})

1) We have the 2 equations:
[1]: a + b = 4
[2]: a -2b = 1
2) Solving for a: a + b = 4 [1]
Solution obtained [1]: a = 4 -b
3) Solving for b: a -2b = 1 [2] where a = 4 -b
ⓘ Group like terms by adding their coefficients: -b -2b = -3b
4 -3b = 1
ⓘ We gather the terms in b on the right and the other terms on the left
4 -1 = 3b
ⓘ Start from 4 and move back 1 on the number line: 4 -1 = 3
3 = 3b
ⓘ Divide both sides by 3
b = 33
ⓘ We simplify the fraction by dividing the numerator and the denominator by 3, their greatest common divisor: 33 = 1
Solution obtained [2]: b = 1
4) You can compute the value of a based on: a = 4 -b where b = 1
a = 4 -1
ⓘ Start from 4 and move back 1 on the number line: 4 -1 = 3
Solution obtained: a = 3
▶Solution:   { a = 3, b = 1 }

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