Word problem frustration?

Question

Please help me with this

Edd has 81000 dollars invested in stocks at 7% how much additional money should he invest in certificates of deposit paying 3% so that the average return of the investments is 4%

the answer is 243000 im pretty sure but how do you solve it?

Answer 1

0.03X + (81,000 * 0.07) = 0.04 * (X + 81,000)

0.03X + 5,670 = 0.04X + 3,240

0.03X + 2,430 = 0.04X

2,430 = 0.01X

243,000 = X