Answer
See explanation.
Work Step by Step
a. Charge and the number of nucleons are conserved. The new Z is 2 + 3 = 5. The new A is 4 + 7 - 1 = 10.
b. Calculate the mass change in the reaction. The nuclide X is boron-10. Use the atomic masses to calculate the mass defect of $-2.994\times10^{-3}u$, the total masses on the left minus the total masses on the right. The negative sign means there is more mass afterward than before.
This equals an energy of 2.79 MeV of energy that was absorbed. The absorbed energy probably came from the initial kinetic energy of the helium and lithium.