Answer:
3x^2 + 10x
Step-by-step explanation:
Answer:
-1960
Step-by-step explanation:
The expression on the left expands to ...
(4x -7)² = (4x)² +2(4x)(-7) +(-7)² = 16x² -56x +49
Matching coefficients, you have ...
Then the expression c(b+a) evaluates to ...
49(-56+16) = 49(-40) = -1960
Answer:
2870
Step-by-step explanation: mind
Answer:
343 : 729
Step-by-step explanation:
A cube is made up of 6 square faces. If each face has a side length of a, we can find the surface area of that cube with the formula 
, since we'll have 6 faces with area a². Let's call the edge length of the first cube a and the edge length of the second cube b. The ratio between their surface areas is then 6a² : 6b², or simply a² : b². If we compare this to our given ratio 49 : 81, we can see that a² = 49 and b² = 81, or, square rooting both equations, a = 7 and b = 9.
The volume of a cube with a side length a is a³, so the ratio between our cubes here must be a³ : b³. Using the values for a and b we just found, this ratio becomes 7³ : 9³, which we can simplify to 343 : 729.
