2х^2+5х^2-7=0

To solve the quadratic equation \(2x^2 + 5x^2 - 7 = 0\), first combine like terms: \[ (2 + 5)x^2 - 7 = 0 \] \[ 7x^2 - 7 = 0 \] Next, add \(7\) to both sides: \[ 7x^2 = 7 \] Now, divide both sides by \(7\): \[ x^2 = 1 \] Taking the square root of both sides gives: \[ x = \pm 1 \] Thus, the solutions to the equation \(2x^2 + 5x^2 - 7 = 0\) are: \[ x = 1 \quad \text{and} \quad x = -1 \]