Question

To solve this system of equations using substitution what could be substituted in place of Y in the first equation 4x=5-2y y-2x+7

Answer 1

To solve this system of equations using substitution, y value to be substituted is 2x – 7.

Solution:

Given, two system of equations are 4x = 5 – 2y and y – 2x + 7 = 0

We have to find what substitution have to be done in place of y of the first equation to solve the given system of equations.

Now, let us derive the y value from 2nd equation ⇒ y – 2x + 7 = 0 ⇒ y = 2x – 7

We have got the y value, and we can substitute it in 1st equation ⇒ 4x = 5 – 2(2x – 7)

4x = 5 – 4x + 14

4x + 4x = 5 + 14

8x = 19  

$x=\frac{19}{8} \text { and } y=2\left(\frac{19}{8}\right)-7=\frac{19}{4}-7=\frac{19-28}{4}=\frac{-9}{4}$

So, solution for system of equations is $\left(\frac{19}{8}, \frac{-9}{4}\right)$

Hence, the y value to be substituted is 2x – 7.