WAEC - Mathematics (2013 - No. 12)
If \(\frac{1}{2}\)x + 2y = 3 and \(\frac{3}{2}\)x - 2y = 1, find (x + y)
3
2
1
5
ব্যাখ্যা
\(\frac{1}{2}\)x + 2y = 3......(i)(multiply by 2)
\(\frac{3}{2}\)x - 2y = 1......(ii)(multiply by 2)
x + 4y = 6......(iii)
3x - 4y = 2.....(iv) add (iii) and (iv)
4x = 8, x = \(\frac{8}{4}\) = 2
substitute x = 2 into equation (iii)
x + 4y = 6
2 + 4y = 6
4y = 6 - 2
4y = 4
y = \(\frac{4}{4}\)
= 1(x + y)
2 + 1 = 3
\(\frac{3}{2}\)x - 2y = 1......(ii)(multiply by 2)
x + 4y = 6......(iii)
3x - 4y = 2.....(iv) add (iii) and (iv)
4x = 8, x = \(\frac{8}{4}\) = 2
substitute x = 2 into equation (iii)
x + 4y = 6
2 + 4y = 6
4y = 6 - 2
4y = 4
y = \(\frac{4}{4}\)
= 1(x + y)
2 + 1 = 3