Question

If x^2 -7x=30 and x>0, what is the value of x-5

Answer 1

5

Explanation:

x^2-7x=30

x^2-7x-30=0

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

sqrt(b^2-4ac)

sqrt(49+120)

sqrt(169)

13

-b +/- 13

7 + 13 = 20

7 - 13 = -6

2a = 2

20/2 = 10

-6/2 = -3

we know x>0, so it cant be -3. so now its just 10 - 5