Question

Solve the equation x2 + + 7x= 30

O A. x= 15 and x= -2
0 B x=-6 and x = 5
0 C x= -10 and x= 3
O D. x= 10 and x= -3

Answer 1

The equation x^2 + 7x = 30 can be solved by rearranging to standard form and using the quadratic formula, which gives the solutions x = 3 or x = -10. The correct answer is x = -10 and x = 3.

Step-by-step explanation:

To solve the equation x2 + 7x = 30, we can first rearrange the equation to standard quadratic form by subtracting 30 from both sides to get x2 + 7x - 30 = 0. Next, we can solve the quadratic equation either by factoring, if possible, or by using the quadratic formula: x = ∛(-b ± √(b2 - 4ac)) / (2a), where a = 1, b = 7, and c = -30. After finding the discriminant b2 - 4ac (which is 49 - 4(1)(-30) = 49 + 120 = 169), we can see that it is a perfect square. Thus, the roots can be found easily:

x = ∛(-7 ± √(169)) / 2 = ∛(-7 ± 13) / 2 = ∛(6) / 2 or ∛(-20) / 2

Which gives us two solutions: x = 3 or x = -10.

Answer 2

x^2+7x=30

x^2+7x-30=0

Here a=1,b=7 and c=-30

Now,

Discriminant(D)=b^2-4ac

=7^2-4×1×(-30)

=49+120=169

By applying Quadratic formula

x=-b+- root over b^2-4ac÷2a

=-7+- root over D ÷ 2×1

=-7 +- root over 169 ÷2

=-7 +- 13 ÷2

Now,

Either x=-7+13÷2=6÷2=3

Or x=-7 -13 ÷2=-20÷2=-10

Hence, ans is (C) x=-10 and x=3