Question 79·Easy·Equivalent Expressions
Which expression is equivalent to ?
For “equivalent expression” questions, systematically simplify the given expression yourself: expand any products or powers (using FOIL or special-product formulas), carefully distribute any minus signs across parentheses, and then combine like terms. Work step by step to avoid sign errors—especially when subtracting an entire expression—and only at the end match your simplified result to the answer choices; if you’re unsure, you can quickly check by substituting a simple value like into both your result and the choices to see which one agrees.
Hints
Start by expanding
Rewrite each part as a product and expand: is , and is already written as a product.
Use special-product formulas
For , use the square of a binomial formula. For , recognize it as a difference of squares: .
Be careful with the subtraction
After you expand both parts, you will have something like one polynomial minus another polynomial. Make sure you subtract every term in the second polynomial (distribute the negative sign) before combining like terms.
Desmos Guide
Graph the original expression
Type y1 = (3x - 2)^2 - (x - 4)(x + 4) into Desmos. This creates the graph of the original expression.
Graph each answer choice
On new lines, enter each option as its own function, for example:
y2 = 8x^2 - 12x + 20y3 = 8x^2 + 12x - 20y4 = 10x^2 - 12x - 20y5 = 8x^2 - 12x - 20Each one will appear as a separate parabola.
Compare the graphs
Look at the graph of and see which one of , or lies exactly on top of it for all visible -values. The expression whose graph perfectly overlaps is the one equivalent to the original expression.
Step-by-step Explanation
Recognize the structures to expand
The expression has two parts:
- : a binomial squared.
- : a product of conjugates (same terms, opposite signs).
To simplify, expand each part into standard polynomial form, then subtract.
Expand
Use the formula with and :
So the first part becomes .
Expand and rewrite the whole expression
is a difference of squares: with and .
Now substitute both expansions into the original expression:
Distribute the minus sign and combine like terms
First, distribute the minus sign across the second parentheses:
Now combine like terms:
- stays
So the simplified expression is , which matches answer choice A.