tan‌A=x,‌‌cos‌B=y,sin‌C=z x+3y+6z=1 . . . (i) 3x+y+4z=4 . . . (ii) 5x+3y−8z=−2‌‌...‌ (iii) ‌ On subtracting Eq. (iii) from Eq. (i), 4x−14z=−3 . . . (iv) Multiply by 3 in Eq. (ii) and subtracting if from Eq. (i) −8x−6z=−11‌‌...(v) Multiply by 2 in Eq. (iv) and adding Eqs. (iv) and (v) −34z=−17 The value of z=‌
1
2
,x=1 ∴‌‌tan‌A=1‌ and ‌y=−1 A‌‌=‌