Question

find value of m-n,if m+n=7,mn=12

Answer 1

we know that,(a + b) {?}^{2} { = (a - b) }^{2} + 4ab \\ then.. \\ 7 { }^{2} = (m - n) { }^{2} + 4 \times 12 \\ 49 - 48 = (m - n) { \\ }^{2} m - n = 1