The desired answer is probably that 2x + 1 = 67 is the equation that can be used to solve the problem. In this case, x represents the smallest integer.
_____ I like to work problems in consecutive integers by considering their average. Here, it is 67/2 = 33.5. The two consecutive integers whose average is 33.5 are 33 and 34, the solution to the problem. For this, the first equation applies, where x is the value halfway between the two integers. (This answer (2x=67) would likely get marked wrong by your computer grading system.)
"Completing the square" is one of many different techniques for solving a quadratic equation. What you do is add a constant to both sides of the equation such that the lefthand side can be factored into the form a(x+d)^2. For instance, squaring (X+D) = X^2 + 2DX + D^2. Notice the 2DX term. That is the same term as the 15x term in the problem. So 2D = 15, D = 7.5. And D^2 = 7.5^2 = 56.25. So we have
x^2 + 15x + 56.25 = 49 + 56.25
Which is
x^2 + 15x + 56.25 = 105.25 Which is the answer desired.
Now the rest of this is going beyond the answer. Namely, it's answering the question "Why does complementing the square help?"
Well, we know that the left hand side of the equation can now be written as
(x+7.5)^2 = 105.25
Now take the square root of each side
(x+7.5) = sqrt(105.25)
And let's use both the positive and negative square roots. So
x+7.5 = 10.25914226
and
x+7.5 = -10.25914226
And let's find X.
x+7.5 = 10.25914226
x = 2.759142264
x+7.5 = -10.25914226
x = -17.75914226
So the roots for x^2 + 15x - 49 is 2.759142264, and -17.75914226</span>
P= principal (initial deposit) ($7000) i= interest (5%) t= # of years (3)
Total amount = P (1 + i)^t T= $7000(1 + 5%)^3 T= 7000(1.05)^3 multiply exponents before regular multiplication T= 7000(1.157625) Total= $8,103.38 after 3 years
