x 2 + y + 7 = 7 20 x + 100 - y = 0 The solution to the

Question

x 2 + y + 7 = 7 20 x + 100 - y = 0 The solution to the given system of equations is x , y . What is the value of x ?

Accepted Answer

The correct answer is - 10 . Adding y to both sides of the second equation in the given system yields 20 x + 100 = y . Substituting 20 x + 100 for y in the first equation in the given system yields x 2 + 20 x + 100 + 7 = 7 . Subtracting 7 from both sides of this equation yields x 2 + 20 x + 100 = 0 . Factoring the left-hand side of this equation yields x + 10 x + 10 = 0 , or x + 10 2 = 0 . Taking the square root of both sides of this equation yields x + 10 = 0 . Subtracting 10 from both sides of this equation yields x = - 10 . Therefore, the value of x is - 10 .

Question x-2-y-