How fo I substitute

-x+y=-13

3x-y=19

The ratio of Monarch butterflies to Queen butterflies at a butterfly farm was 5:2. If there are no additional butterflies at the farm, what is the ratio of Queen butterflies to the total number of butterflies at the farm? A. 2:7 B. 5:7 C. 7:2 D. 7:5

Han ran 10 meters in 2.7 seconds. Priya ran 10 meters in 2.4 seconds. Who is faster?

Add: 3x (x-y+z) and 2y (x+y-z)

Efrain must spend less than $80 on his phone bill this month. He pays a monthly fee of $16, plus an additional $4 for each long-distance call. 4x + 16 < 80 How may long-distance calls can Efrain make this month? A. x<16 B. x<48 C. x<4 D. x<64

A glass dome for a lighting fixture is in the shape of a hemisphere. The circumference of the great circle of the hemisphere is 12π inches. Which statements about the hemisphere are true? Check all that apply. The radius is 6 inches.

What is the vertex of the function in #5

he mass of a single atom of carbon can be found by dividing the atomic mass (12.01 g) by 6.022 x 10^23. Which is the mass of a single carbon atom, correctly written in scientific notation with the correct number of significant figures?

The value of the 2 in 204.75 is how many times the value of the 2 in 103.52

A+b=s+r for s I have no idea how to solve this

What is the degree of a polynomial that has roots of - 2, 4i and - 4i?