Question

Use the quadratic formula to solve the equation. If necessary, round to the nearest hundredth. x^2+3=-4x

a. 1,3
b. -1, -3
c. 1, -3

Answer 1

add 4x to both sides
x^2+4x+3=0
we don't need quadratic formula, just factor
what 2 numbers multiply to get 3 and add to get 4
3 and 1
(x+3)(x+1)=0
set to zero

x+3=0
x=-3

x+1=0
x=-1

x=-11,-3

B is answer

Answer 2

The general form of the quadratic equation is,
ax² + bx + c = 0
The general form of the equation given above is,
x² + 4x + 3 = 0
Using quadratic formula for solving the values of x,
x = ((-b) +/- sqrt(b² - 4ac)) / 2a
Substituting,
x = ((-4) +sqrt(4² - 4(1)(3)) / 2(1) = -1
x = ((-4) -sqrt(4² - 4(1)(3)) / 2(1) = -3
Thus, the values of x are -1 and -3. The answer is letter B.