Which figure must be a square?
a.
a quadrilateral with four right angles
b.
a rhombus with four right angles
c.
a parallelogram with four congruent sides
d.
a quadrilateral with congruent sides

Use addition and subtraction to simplify the following polynomials. a. add polynomials: (3 – 4x + 8x^2) + (–6 + 2x – 5x^2) step 1: rewrite the polynomials without the parentheses. step 2: write the polynomial in descending order and use parentheses around like terms. step 3: add the like terms identified in step 2 to simplify the polynomial. b. subtract polynomials: (3x – 5 – 7x^2) – (–2 + 6x^2 – 5x) step 1: rewrite the polynomials without the parentheses. remember to multiply each term in the second parentheses by –1. show your work. step 2: write the polynomial in descending order and use parentheses around like terms. step 3: add the like terms identified in step 2 to simplify the polynomial.

If x + 10 = 70, what is x? a. 40 b. 50 c. 60 d. 70 e. 80

Need on this geometry question. explain how you did it.