WAEC - Mathematics (1991 - No. 13)
If 2x + y = 7 and 3x - 2y = 3, by how much is 7x greater than 10?
1
3
7
10
17
คำอธิบาย
2x + y = 7 = i
3x - 2y = 3 = ii
i x 2 + ii = 4x + 2y = 14
\(\frac {3x - 2y = 3}{7x = 17}\)
x = \(\frac {17}{7}\) = 7x = 17 x 1/7 x 7
17 - 10 = 7
3x - 2y = 3 = ii
i x 2 + ii = 4x + 2y = 14
\(\frac {3x - 2y = 3}{7x = 17}\)
x = \(\frac {17}{7}\) = 7x = 17 x 1/7 x 7
17 - 10 = 7