Question

What value of g makes the equation true? (x-3)(x+5)=x2+gx-15
–8
 –2
2
 8

Answer 1

Answer: g = 2

We can find the value of g by expanding the left hand side of the equation and comparing the left side with right side.

$(x-3)(x+5)= x^{2} +gx-15 \\ \\ x^{2} +5x-3x-15= x^{2} +gx-15 \\ \\ x^{2} +2x-15= x^{2} +gx-15$

Comparing the two sides of the equation, we can conclude that the value of g is 2. Therefore correct answer is 3rd option