substitution method
Step-by-step explanation:
- use second equation
- make x subject of the formula
- put it back in the first equation
- solve to find the value of y
- substitute y value in any equation between the two.
- then you get x value
Answer:

Step-by-step explanation:
Density is defined as mass of an object divided by its volume.
#We calculate the volume of the cylinder:

Given the mass= 15.3kg and volume as above, we calculate density as:

Hence, the solid's density is 
810
all you need to do is plug in 12 for a and 7 for p. the you solve it.
8*12=96
7*4=28
96+28+11=135
6(135)=810
Answer:
$6.61
Step-by-step explanation:
3 * 1.89 = 5.67
1.89/2 = 0.945
5.67 + 0.945 = 6.615
= 6.61