Solve each system by substitution. 1) 2x - 6y = 18
x + 3y = -21

2)y = 2x + 7
2x - y = -3

3) -5x + 6y = -9
3x - 4y = 5

4) -x + 7y = 10
y = 5x - 18

5) y = 4x + 8
y = 5x + 10

6) x + 5y = -7
-5x - 4y = 14

7) -21x + 12y = -9
7x - 4y =3

8) y = -4x - 23
y = 4x + 9

Write an algebraic expression to match each statement a. four less than 8 times a number b. twice the difference of a number and six c. nine from a number squared

Acompany manufactures large valves, packed in boxes. a shipment consists of 1500 valves packed in 75 boxes. each box has the outer dimensions 1.2 x 0.8 x 1.6 m and the inner dimensions 1.19 x 0.79 x 1.59 m. the boxes are loaded on a vehicle (truck + trailer). the available capacity in the vehicle combination is 140 m3. each valve has a volume of 0.06 m3. - calculate the load factor on the box level (%). - calculate the load factor on the vehicle level (%). - calculate the overall load factor (%).

Marcus and cody both leave the park at the same time, but in opposite directions. if cody travels 6 mph faster than marcus and after 4 hours they are 64 miles apart, how fast is each traveling? solve using rare times time = distance.