I- huh I don’t understand the question
It is the last equation. You square both sides.
Money invested S + B = $5000 - - - - (a)
Money earned can be represented in S & B as follows:
0.07*S + 0.14*B =$500 - - - - (b)
Equations a & b are two equations with two unknowns.
From equation a:
S = 5000 - B
Replace S in equation b
0.07*(5000 - B) + 0.14*B =$500
0.07B = 500 - 350 = $150
B = 150/0.07 = $2142.86
S = 5000 - 2142.86 = $2857.14
Good luck
It would be C as no multiple of 3 can equal 13