The values of a and b in the sytem of equation are 12 and 9 respectively.
How to find the variables(a and b) in the sytem of equation?
b = 3 / 4 a
a + b = 21
Therefore, let's substitute b in equation(ii)
a + b = 21
a + 3 / 4 a = 21
4a + 3a / 4 = 21
7a / 4 = 21
cross multiply
7a = 21 × 4
7a = 84
divide both sides by 7
a = 84 / 7
a = 12
b = 3 / 4 a
b = 3 / 4 × 12
b = 36 / 4
b = 9
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