d) You have a <u>difference of squares</u>:
49y² - 9 = (7y)² - 3²
Recall the identity,
a² - b² = (a - b) (a + b)
So,
49y² - 9 = (7y - 3) (7y + 3)
e) Pull out the common factor 3 from each term:
3x² - 3x - 90 = 3 (x² - x - 30)
Now use the <u>sum-product method</u>. Notice that we can write 30 = 5 • 6, and 5 - 6 = 1, so
3x² - 3x - 90 = 3 (x + 5) (x - 6)
f) Same as in (e), use the <u>sum-product method</u>. Notice that 42 = 7 • 6, and -7 - 6 = -13, so
x² - 13x + 42 = (x - 7) (x - 6)
Vol (pyr) = 1/3 b × h, where h = 15 and b = base = area of triangular base = 1/2 b×h, where h = 12 and b = 13
V = 1/3 (1/2×12×13)×15
V = (1/3×1/2×12)×13×15
V = 2×13×15 = 30×13 = 390 in^3
Answer:
B
Step-by-step explanation:
x% of 6 = 5.25
x 6 = 5.25
= x
x = 87.5 %
discount = 100 - 87.5 %
= 12.5 %
Answer:
120 cm
Step-by-step explanation:
One way to tackle this is by getting another sheet of paper and drawing it out, then counting up the total of the sides. If you draw it, you can see that you're dealing with a rectangle; two sides of length 12 and two sides of length 8. If you don't like drawing or don't want to in this case, another way to get the answer is by knowing one vertex is at (0, 0), so the next vertex (0, 8), would create a side that's exactly 8 units long. Kind of the same, you know from (0, 0), you also have a point (12, 0), so drawing that would create a side that's 12 units long. All in all, to get the perimeter in units, you have 12 + 12 + 8 + 8 = 40.
The problem says it wants the amount of wood in centimeters needed for the perimeter. What we just found was the perimeter in generic units, so if the problem says every "grid square", or unit, is 3 centimeters long, then all you have to do is take our result 40 and multiply it by 3 to get the number of centimeters. Your perimeter in centimeters would be 120 cm.
10 cupcakes in total
1/5 of 10 is 2/10 so 2 cupcakes are chocolate
2*0.45=$0.90
Dora spent $0.90 on chocolate cupcakes
