Question 179·200 Super-Hard SAT Math Questions·Advanced Math
The real numbers and satisfy the system
Which choice is the value of ?
For radical systems, substitute variables for each square root (for example, and ) so the equations become algebraic. Then look for quick identities like to connect a known difference to a needed product. Finally, rewrite the target expression (here, ) in terms of and and use and to avoid solving for and directly. aniko.ai
Hints
Try a substitution
Let and . Rewrite both equations using and . Contеnt bу Аnikο.аi
Connect the second equation to
From and , rewrite as an equation involving .
Use an identity to get
Square to create , then use your value of to find .
Compute efficiently
Write and expand. Replace with and replace with the value you found.
Desmos Guide
Enter the system
Graph the line .
Then graph the equation (you can type it exactly as written; Desmos will graph it as an implicit curve).
Find the intersection point
Click on the intersection of the two graphs and create a point (for example, point ). Propеrty оf Aniko.ai
Compute the product at the intersection
In a new expression line, type A.x*A.y.
Match that value to the answer choice.
Step-by-step Explanation
Substitute to remove the square roots
Let and . Then and , and the system becomes
Convert into a sum of squares
From ,
so
Use to find the product
Square the equation : Wrіtten by Anікo
Substitute :
Rewrite in terms of and
Since and ,
Use and :
Substitute and compute
Substitute and :
So the correct choice is .