For an acute angle A, sec A + tan A = 3…

Step 1. Factorise the identity. $(\sec A + \tan A)(\sec A - \tan A) = 1$, so $3(\sec A - \tan A) = 1$.

Step 2. The difference. $\sec A - \tan A = \dfrac{1}{3}$, which is $0.333$.

Step 3. Add. $2\sec A = 3 + \dfrac{1}{3} = \dfrac{10}{3}$, so $\sec A = \dfrac{5}{3}$, which is $1.667$.

Step 4. Subtract. $2\tan A = 3 - \dfrac{1}{3} = \dfrac{8}{3}$, so $\tan A = \dfrac{4}{3}$, which is $1.333$.