Help me with this math problem please

Step-by-step explanation:

Note that the entire segment RT is the combined lengths of RS and ST. So:

We know that RT is 108, RS is (9y+5), and ST is (3y+7). Substitute:

On the right, combine like terms:

Add:

Subtract 12 from both sides. The right cancels:

Divide both sides by 12:

So, the value of y is 8.

To find RS and ST, substitute 8 for y. So:

Substitute 8 for y:

Multiply:

Add:

Do the same for ST:

Substitute 8 for y:

Multiply:

Add:

what are ur choices?

51

step-by-step explanation:

73-22=51 the   mass number minus the amount of protons gives you the amount of neutrons