Hello! can someone me with a substitution problem? pre-alg level.

3x+9y=42
y=2x

x=2

Step-by-step explanation:

The equation becomes 3x+9(2x)=42. Then you distribute the 9 into the 2x. Combine 3x and 18x for 21x=42. Divide 21 by both sides and you get x=2.

(x3 + 6x2 + 2x - 6) • (x - 1)

step-by-step explanation:

polynomial long division :

3.2     polynomial long division

dividing :   x4+5x3-4x2-8x+6

                              ("dividend")

by         :     x-1     ("divisor")

dividend     x4   +   5x3   -   4x2   -   8x   +   6

- divisor   * x3     x4   -   x3            

remainder         6x3   -   4x2   -   8x   +   6

- divisor   * 6x2         6x3   -   6x2        

remainder             2x2   -   8x   +   6

- divisor   * 2x1             2x2   -   2x    

remainder               -   6x   +   6

- divisor   * -6x0               -   6x   +   6

remainder                     0

quotient :   x3+6x2+2x-6   remainder:   0

1. which statement below is true for hyperbolic geometry?

answer: d  

the sum of the measures of the angles in a triangle is always less than 180 degrees.

2. identify the statement that is true in spherical geometry.

answer: d  

the sum of the measures of the angles of a triangle is greater than 180.

3. what can be said about the vertices of an equilateral triangle drawn in poincaré’s system?

answer: b  

the vertices are equidistant from the center of the circle.

4. satellites sputnik, yeltsin, and plekov often temporarily line up in order in a great circle. the circumference of the earth is 24,900 miles, and the satellites orbit at about 150 miles above the surface. if, while in a great circle, sputnik is 9,000 miles from yeltsin, and yeltsin is 10,500 miles from plekov, how far apart are sputnik and plekov?

answer: b  

6,342 miles

5. identify the statement that is true in spherical geometry.

answer: d  

two distinct lines intersect in two points.