Use the method of substitution to solve the system of linear equations.

Question

3x+5y=3/4

y=4x-1

What's the solution? (Type an ordered pair, using integers or fractions) 

Answer 1

If y=4x+1 then everytime you see y in the original equation, you put in 4x+1---

Thus--

3x+5y=3/4 becomes

3x+5(4x-1)=3/4

use the distributive property--

3x+20x-5=3/4

23x=5.75        (I changed 3/4 to.75)

x=.25   or 1/4

put .25 in the equation for x

3(.25) +5y=.75

.75+5y=.75

5y=-0

y=-0

 

check---

3(.25) +5(0)=.75

.75=.75