Question

X = y2 - 1

Answer 1

Answer:

Option (2) is correct.

$2y^2-y-6=0$

Step-by-step explanation:

Given two equations $x=y^2-1$ and $2x-y=4$

We have to choose an equation from the given options which could be the result of using substitution to solve the system.

Since the given equation is in term of y , so we make substitution of x in term of y.

From $2x-y=4$,

⇒ $x=\frac{4+y}{2}$

Substitute  $x=\frac{4+y}{2}$  in other equation $x=y^2-1$

We get, $x=y^2-1 \Rightarrow \frac{4+y}{2}=y^2-1$

Cross multiply we get,

$\Rightarrow {4+y}=2y^2-2$

Solving further, we get

$\Rightarrow 2y^2-y-6=0$

Thus, option (2) is correct.