Question

find the value of 2x² - 5x - 3 = 0 by using quadratic formula​

Answer 1

Answer:

ans is X=1

Step-by-step explanation:

2x²-5x-3=0

3x²-3=0

x²=3÷3

X=✓1

ans is X=1

Answer 2

Given-

• $\bf2 {x}^{2} - 5x - 3 = 0$

Concept used

• $\bf discriminant$
• $\bf d = {b}^{2} - 4ac$

• $\bf quadratic \: formula$
• $\bf \: x = \frac{ - b \pm \sqrt{d} }{2a}$
• $\bf factorisation$

$\bf \huge { solution}$

Factorisation

$\bf 2 {x}^{2} - 6x + x - 3 = 0 \\ \bf \implies 2x(x - 3) + 1(x - 3) = 0 \\ \bf \implies \: 2x + 1 = 0 \: or \: x - 3 = 0 \\ \implies \boxed{ \bf \: x = \frac{ - 1}{2} \: or \: 3 }$

Quadratic equation

Discriminant

$\bf \: d = {b}^{2} - 4ac$

Here,

• a=2
• b=-5
• c=-3

$\bf d = { (- 5)}^{2} - 4 \times 2 \times - 3 \\ \implies \bf \: d =25 + 24 \\ \implies \boxed{\bf \: d = 49}$

Using quadratic formula

$\bf \: x = \frac{5 \pm \sqrt{49} }{2 \times 2} \\ \bf x = \frac{5 \pm \: 7}{4} \\ \bf \implies \: x = \frac{12}{4} or \: \frac{ - 2}{4} \\ \implies \boxed{ \bf x = 3 \: or \: \frac{ - 1}{2} }$