Question

Use substitution to write an equivalent quadratic equation.
(3x + 2)2 + 7 (3x + 2) – 8 = 0
-
u2 + 74 - 8 = 0, where u = (3x + 2)2
u2 + 7u - 8 = 0, where u = 3x + 2
u2 + 70 - 8 = 0, where u = 7(3x + 2)
lu² +4-8=0
What’s the answer?

Answer 1

For this case we can make a change of variable, to obtain a quadratic equation of the form:

$ax ^ 2 + bx + c = 0$

Making the change:$u = 3x + 2$

Substituting the change we have:

$u ^ 2 + 7u-8 = 0$

Thus, the correct option is:$u ^ 2 + 7u-8 = 0$where $u = 3x + 2$

Answer:

Option B

Answer 2

Answer:

second option: $u^{2}+7u-8=0$

Step-by-step explanation:

We have the equation given:

$(3x+2)^{2}+7(3x+2)-8=0$

We can replace the variable in the quardatic equation.

So,

$Putting\\u=3x+2$

Putting u in place of 3x+2 will give us:

$(u)^{2}+7(u)-8=0$

So the answer is:

$u^{2}+7u-8=0$

So, the second option is correct ..