*remember that in standard form you cant use ! give me the standard form of this equation.

Let us assume Maricopa invested X amount in CDs, then she would have invested X+30000 in bonds

We know Amount Invested in CDs + Amount invested in Bonds + Amount Invested in Stocks = 90000

As we earlier discussed Amount Invested in CDs = X, Amount Invested in X + 30000 putting these in above equation

X + X + 30000 + Amount invested in stocks = 90000

2X+ 30000 + Amount invested in stocks = 90000

Taking 2X + 30000 to right hand side of equation  

Amount invested in stocks = 90000 - 30000 - 2X

= 60000 - 2X

Now Interest on CDs = 4.25 % * Amount invested in CDs = 4.25/100 * X =  0.0425 X

Interest on bonds = 4.3/100 % * Amount invested in Bonds = 4.3/100 * (30000 + X)= 1290 + 0.043X  

Interest on stocks = 8.6/100% * Amount invested in stocks = 8.6/100 * (60000 - 2X) = 5160 - 0.172X

Total Interest = 5153

Adding all the interest calculated

0.0425X + 1290+ 0.043X + 5160 - 0.172X = 5153

(0.0425X + 0.043X - 0.172X) + (1290+5160) = 5153

-0.0865 X + 6450 = 5153

0.0865 X = 6450 - 5153

0.0865 X = 1297

X = 15000

CDs amount = $15000

Bonds amount = $45000

Stocks amount = $30000