Question

7x2 + 10x = -3


A. 3/7, -1
B. -3/7
C. -3/7, 1
D. -3/7, -1
E. None of the above

Answer 1

D

Answer 2

Add three to both sides to set the equation equal to zero.
Then factor 7x^2 + 10x +3.
Here's a good factoring calculator: http://www.freemathhelp.com/factoring-calculator.php
Once you have the factors, set each one equal to zero and solve for the variable. :)

Answer 3

@$Young_Money$ 7x2-10x-8=0
7x2 -10x -8 = 0
ax2 bx c = 0
a = 7
b = -10
c = -8
Δ = b2-4ac
Δ = -10² - (4 * 7 * -8)
Δ = 100 - (4*-56)
Δ = 100 - (-224)
Δ = 324 Δ > 0
7x2-10x-8=0
x =
-b ∓ √Δ
2a
x' =
10 - √324
2*7
=
10 - 18.0
14
=
-8.0
14
= -0.571428571429
x" =
10 + √324
2*7
=
10 + 18.0
14
=
28.0
14
= 2.0
x' = -28.0
x" = 98.0
S = {x ∈ R / x' = -28.0, x" = 98.0 }