Solve and Substitute (Substitution)

Solve the following systems of equations with substitution:

1. $\eqalign{2x&=4y\\3x+5&=y}$

    

2. $\eqalign{x&=2y\\-3x+8y&=12}$

    

3. $\eqalign{-x+1&=3y\\5x-7&=10y}$

    

4. $\eqalign{x-2&=2y\\20x-18&=2y}$

    

5. $\eqalign{-2x&=y-8\\-x+15y&=19}$

    

6. $\eqalign{.5x&=4y\\2x+2&y=2}$

    

7. $\eqalign{\dfrac{1}{2}x&=6y\\2y-5x+5&=15}$

    

8. $\eqalign{5x-3&=3y+7\\2x-11&=y+19}$

    

9. $\eqalign{21x&=7y\\15x+15y&=29}$

    

10. $\eqalign{-x&=-8y\\-5x+9&=9y}$