ANSWER
The largest angle is
![56.2 \degree](https://img.qammunity.org/2020/formulas/mathematics/high-school/sp8m8pv54bn8141mbpqrc223vqxugn3f0t.png)
Step-by-step explanation
If two angles are complementary, then they must sum up to 90°.
The given angles are
![(3x + 10) \degree](https://img.qammunity.org/2020/formulas/mathematics/high-school/s1ogt4z49ha7rp3bnmt8u4m7stnd4ewbo5.png)
and
![(2x + 3) \degree](https://img.qammunity.org/2020/formulas/mathematics/high-school/vh1xls39ketgf8ta0oi03a6vrkojf5m3bx.png)
Their sum must give us 90°.
This implies that,
![(3x + 10) + (2x + 3) = 90](https://img.qammunity.org/2020/formulas/mathematics/high-school/5k7yvj5gj6keel1jf2ohwlmnmfxxj1ndvk.png)
We group like terms to get,
![3x + 2x = 90 - 10 - 3](https://img.qammunity.org/2020/formulas/mathematics/high-school/rb3zsxq0wmmiib2on0i3lwa2qxm5lqtear.png)
This gives,
![5x = 77](https://img.qammunity.org/2020/formulas/mathematics/high-school/tozapm973w0vm02caxniegk30lxdi8f910.png)
Divide both sides by 5 to get,
![x = (77)/(5)](https://img.qammunity.org/2020/formulas/mathematics/high-school/ox70p2eqtjhjrj7abi87fuyliziwsw6ui4.png)
![x = 15.4](https://img.qammunity.org/2020/formulas/mathematics/high-school/cirtkzuyu5hsttqwbuqgidcq99p1i5lyuw.png)
The largets angle is
![3(x) + 10](https://img.qammunity.org/2020/formulas/mathematics/high-school/5rom47xct7jokjwg6pw5e44mf130nksb1q.png)
![=3(15.4) + 10](https://img.qammunity.org/2020/formulas/mathematics/high-school/2leov04ygj54h0p4a5syicyggx2tpvqa8y.png)
![=46.2+ 10 = 56.2\degree](https://img.qammunity.org/2020/formulas/mathematics/high-school/laqsihbl8a5ppo3mqnsc712bmklx4mvpq0.png)
The correct answer is D