x^2-13x-30=0
A. -3,-10
B. 3,10
C. -15,2
D. 15,-2
x^+7x-18=0
A. -9,2
B. -6,3
C. -3,6
D. -2,9
are we solving ?
if so, then ...
x^2-13x-30=0
(x-15)(x+2) = 0
x = 15 or x = -2
the second factors just as easily, try it.
x^2+7x-18=0
A. -9,2
B. -6,3
C. -3,6
D. -2,9
OK SO IS THE ANSWER A???
To find the solutions for both quadratic equations, you can use the quadratic formula.
The quadratic formula is given as:
x = (-b ± √(b^2 - 4ac)) / (2a)
For the equation x^2-13x-30=0, we have a = 1, b = -13, and c = -30.
Substituting these values into the quadratic formula, we get:
x = (-(-13) ± √((-13)^2 - 4(1)(-30))) / (2(1))
Simplifying further:
x = (13 ± √(169 + 120)) / 2
x = (13 ± √289) / 2
x = (13 ± 17) / 2
This gives us two possible solutions:
x = (13 + 17) / 2 = 30 / 2 = 15
x = (13 - 17) / 2 = -4 / 2 = -2
Therefore, for the equation x^2-13x-30=0, the solutions are x = 15 and x = -2.
Comparing these solutions to the given options, the correct answer is D. 15, -2.
Similarly, for the equation x^2+7x-18=0, we have a = 1, b = 7, and c = -18.
Substituting these values into the quadratic formula, we get:
x = (-7 ± √(7^2 - 4(1)(-18))) / (2(1))
Simplifying further:
x = (7 ± √(49 + 72)) / 2
x = (7 ± √121) / 2
x = (7 ± 11) / 2
This gives us two possible solutions:
x = (7 + 11) / 2 = 18 / 2 = 9
x = (7 - 11) / 2 = -4 / 2 = -2
Therefore, for the equation x^2+7x-18=0, the solutions are x = 9 and x = -2.
Comparing these solutions to the given options, the correct answer is D. -2, 9.