197k views
5 votes
Use substitution to solve.

2x² = 5 + y
4y = -20 + 8x²
Solve the first equation for y and substitute it into the second equation. The resulting equation is

2 Answers

5 votes

Answer:

Solve the first equation for y and substitute it into the second equation. The resulting equation is

✔ 8x² - 20 = -20 + 8x²

.

The system has

✔ infinitely many solutions

.

Explanation:

User EchoAro
by
7.9k points
7 votes

2x^2= 5 + y\\ 4y = -20 + 8x^2 \\\\ y=2x^2-5\\ 4y = -20 + 8x^2 \\\\ 4(2x^2-5)=-20+8x^2\\ 8x^2-20=8x^2-20\\ 0=0

The equations are identical. They're satisfied by any pair
(x,2x^2-5) where
x\in\mathbb{R}.
User Daniel Long
by
7.2k points