Физика, 9 класс помогите пожалуйста, вообще в физике не соображаю

1. [latex]^{251}_{98}Cf = ^{211}_{85}At + k*^{4}_{2}He + m*^{0}_{-1}e \\ \\ \left \{ {{251=211+4k} \atop {98=85+2k-m}} \right. \\ \left \{ {{k=10} \atop {m=7}} \right \\ \\ ^{251}_{98}Cf = ^{211}_{85}At + 10^{4}_{2}He + 7^{0}_{-1}e [/latex] Т. е. происходит 10 α-распадов и 7 β-распадов. [latex]^{254}_{99}Es = ^{222}_{87}Fr + k*^{4}_{2}He + m*^{0}_{-1}e \\ \\ \left \{ {{254=222+4k} \atop {99=87+2k-m}} \right. \\ \left \{ {{k=8} \atop {m=4}} \right \\ \\^{254}_{99}Es = ^{222}_{87}Fr + 8^{4}_{2}He + 4^{0}_{-1}e[/latex] Т. е. происходит 8 α-распадов и 4 β-распада. 2. [latex]^{16}_{8}O + ^{1}_{0}n = ^{14}_{7}N + ^{k}_{m}E \\ \\ \left \{ {{16+1=14+k} \atop {8+0=7+m}} \right. \\ \left \{ {{k=3} \atop {m=1}} \right \\ \\^{3}_{1}E = ^{3}_{1}H \\ \\ ^{16}_{8}O + ^{1}_{0}n = ^{14}_{7}N +^{3}_{1}H[/latex] [latex]^{15}_{7}N + ^{4}_{2} \alpha = ^{12}_{6}C + ^{k}_{m}E \\ \\ \left \{ {{15+4=12+k} \atop {7+2=6+m}} \right. \\ \left \{ {{k=7} \atop {m=3}} \right \\ \\^{7}_{3}E = ^{7}_{3}Li \\ \\ ^{15}_{7}N + ^{4}_{2} \alpha = ^{12}_{6}C + ^{7}_{3}Li[/latex] 3. [latex]^{2}_{1}H + ^{3}_{1}H= ^{4}_{2}He + ^{k}_{m}E \\ \\ \left \{ {{2+3=4+k} \atop {1+1=2+m}} \right. \\ \left \{ {{k=1} \atop {m=0}} \right \\ \\^{1}_{0}E = ^{1}_{0}n \\ \\^{2}_{1}H + ^{3}_{1}H= ^{4}_{2}He + ^{1}_{0}n \\ \\ \\^{6}_{3}Li + ^{1}_{1}H= ^{4}_{2}He + ^{k}_{m}E \\ \\ \left \{ {{6+1=4+k} \atop {3+1=2+m}} \right. \\ \left \{ {{k=3} \atop {m=2}} \right \\ \\^{3}_{2}E = ^{3}_{2}He \\ \\^{6}_{3}Li + ^{1}_{1}H= ^{4}_{2}He +^{3}_{2}He [/latex]