What is the next step to solving the following equation by using the quadratic formula? 2n2 - 7n - 3 = 0 n=7±(-7)2-4()2(2)

2n² - 7n - 3 = 0

Δ = b² - 4.a.c

Δ = -7² - 4 . 2 . -3

Δ = 49 - 4. 2 . -3

Δ = 73

There are 2 real roots.

n = (-b +- √Δ)/2a

n' = (--7 + √73)/2.2

n'' = (--7 - √73)/2.2

n' = (7 + √73)/4

n'' = (7 - √73)/4

starting with:    

5 + x - 12 = 2x - 7   

5 + x - 12 - x = 2x - 7 - x (subtract x from both sides)   

5 - 12 = x - 7 (combine and cancel x's from both sides)   

5 - 12 + 7 = x - 7 + 7 (add 7 to both sides)   

0 = x (add numbers together on both sides)       

so in order for the equation to be true, x must be 0.   

trying x = -0.5   

5 + x - 12 = 2x - 7 (original equation)   

5 + -0.5 - 12 = 2(-0.5) - 7 (plug in value of x)   

5 + -0.5 - 12 = -1 - 7 (did multiplication)   

-7.5 = -8 (did addition on both sides)       

since -7.5 is obviously not equal to -8, the value of -0.5 for x is wrong.   

trying x = 0   

5 + x - 12 = 2x - 7 (original equation)   

5 + 0 - 12 = 2(0) - 7 (plug in value of x)   

5 + 0 - 12 = 0 - 7 (did multiplication)   

-7 = -7 (did addition on both sides)       

since -7 equals -7, that demonstrates that the value of 0 for x is correct.   

trying x = 1   

5 + x - 12 = 2x - 7 (original equation)   

5 + 1 - 12 = 2(1) - 7 (plug in value of x)   

5 + 1 - 12 = 2 - 7 (did multiplication)   

-6 = -5 (did addition on both sides)       

since -6 is obviously not equal to -5, the value of 1 for x is wrong.

step-by-step explanation:

graph using a few selected

x         y

-1       15

0         6

1         2.4

2       0.96