(2) multiply the formula y=5.2 by 2 minus 1 and substitute (1) with x=4.5.

2. x=5-T, y-3=2t, t=5-x t=(y-3)/2 respectively.

5-x=(y-3)/2 Simplified 2x+y= 13

3. Use 3x+5y = k+22x+3y = k to solve.

X=2k-6 y=4-k x and Y are only reciprocal, so 2k-6+4+k=0.

k=2/3

4.x and Y are reciprocal, so x+y=0 (x+y+3)(x-y-2)=6.

x=2

5.x+y=2a x-y=6a。 If x= 4a y= -2a substitutes 3X-Y=2, 3*4a-(-2a)=2.

a= 1/7

6. Suppose: x+2=a y- 1=b is substituted into two formulas, and 2a-3b= 13 3a-3b=30.9.

The solution is a=26.9 b= 13.6.

x+2=26.9 x=24.9

y- 1 = 13.6y = 14.6