Answer:
B
Step-by-step explanation:
given the equation
2x² - a = 3x
given x = - 1 is a solution , thensubstitute x = 1 into the equation and solve for a
2(- 1)² - a = 3(- 1)
2(1) - a = - 3
2 - a = - 3 ( subtract 2 from both sides )
- a = - 5 ( multiply both sides by - 1 )
a = 5
The equation is then
2x² - 5 = 3x ( subtract 3x from both sides )
2x² - 3x - 5 = 0 ← in standard form
(x + 1)(2x - 5) = 0 ← in factored form
equate each factor to zero and solve for x
x + 1 = 0 ⇒ x = - 1
2x - 5 = 0 ⇒ 2x = 5 ⇒ x = 2.5
The solutions are x = - 1 and x = 2.5
The other solution is x = 2.5
