Question

Find the solution(s) of the quadratic equation 2x2 – 3x – 35 = 0

Answer 1

Answer: x = 5, x = -7/2

Step-by-step explanation:

2x² - 3x - 35 = 0

Step 1: Find two values whose product = 2(-35) and sum = -3:  -10 & 7

Step 2: Replace the b-value of -3x with  -10x + 7x:

2x² - 10x   + 7x - 35 = 0

Step 3: Factor the first two terms and the second two terms:

2x(x - 5)  +7(x - 5) = 0

Step 4: Write the factored form:

Notice that the parenthesis are identical.  This is one of the factors. The outside values are the other factor:

Parenthesis: (x - 5)

Outside: (2x + 7)

Factored form: (x - 5)(2x + 7) = 0

Step 5: Set each factor each to zero and solve for x:

x - 5 = 0             2x + 7 = 0

   x - 5                      $x=-\dfrac{7}{2}$