Which equations are balanced? Select four options.

-Mg3N2 + H2O → 3MgO + 2NH3

-C3H8 + 5O2 → 4H2O + 3CO2

-Zn + 2HCl → ZnCl2 + H2

-3Ca (OH) 2 + 2H3PO4 → Ca3 (PO4) 2 + 6H2O

-3H2SO4 + 2Fe → Fe2 (SO4) 3 + H2

-4Al + 3O2 → 2Al2O3

5.301 * 10 ^7 in standard form

You have a $90 gift card for a coffee shop. each day you use the card to get a coffee for $4.20. what is the value of the card after buying 8 coffees?

1/6 (30x+24) - 1/7 (63-7x)

At noon, my odometer read 6852 miles. At 3:30 PM, it read 7034 miles. Let t represent the number of hours I have been driving since noon and y represent my odometer reading. Write an equation that relates y and t. Assume constant speed.

Circle A has radius of 4 units. If it takes 10 seconds for one revolution. What is the circumference of circle A? A. 4 ≈ 12.56 B. 8 ≈ 25.12 C. 16 ≈ 50.24 D. 2 ≈ 6.28

A landscaping company ordered 13 plants and 4 trees for the total of $487. If plants are $8 each, write and solve a linear equation to find the cost for each tree.

The result of subtracting two numbers is called finding the

Put in order 2.71, 2. 3/4, square of 5, 5 over 2

What is sin (30 deg) ?

Alban drove 1200 miles in 30 hours. What was his rate of travel in miles per hour? A. 0.025 B. 40 C. 1,230 D. 36,000