Quick solution

/**
 * Returns (x * x) + y
 *
 * @param {number} x – value to be squared
 * @param {number} y – value to add after squaring
 * @returns {number}
 */
function squareAndAdd(x, y) {
    return x * x + y;   // multiplication happens before addition 12
}

How it works

1. x * x computes the square of x using the multiplication operator (*).
2. JavaScript follows standard arithmetic precedence, so the multiplication is performed before the + addition.
3. The result of the multiplication is then added to y and returned.

console.log(squareAndAdd(3, 5));   // → 14  (3*3 + 5)
console.log(squareAndAdd(-2, 10)); // → 14  ((-2)*(-2) + 10)

Alternative: Math.pow

If you prefer a method that reads like “raise to a power”, you can use Math.pow:

function squareAndAdd(x, y) {
    return Math.pow(x, 2) + y;
}

Both versions produce identical results.

Educational variant: multiplication via repeated addition

Sometimes interview or teaching scenarios ask you to build multiplication from addition only. The following demonstrates that concept:

function multiplyByAddition(a, b) {
    // assumes a and b are non‑negative integers
    let result = 0;
    for (let i = 0; i < b; i++) {
        result += a;   // add a, b times 6
    }
    return result;
}

function squareAndAdd(x, y) {
    return multiplyByAddition(x, x) + y;
}

This version shows how x * x can be expressed as multiplyByAddition(x, x).

Edge cases & tips

• Non‑numeric inputs: JavaScript will coerce strings that look like numbers (e.g., "4"), but it’s safer to enforce numeric types with Number(x) or type checking.
• Large numbers: For very large values, consider BigInt (BigInt(x) * BigInt(x) + BigInt(y)).
• Negative numbers: Squaring a negative x still yields a positive result because (-x) * (-x) is positive.