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)
If I did this correctly it simplifies to 0 = 8. So I think B is the correct answer. Hope this helps!!
Equation showing relationships between things you are conparing. An equals sign represents the two expeessions are equal
Answer:
Let x represent number of calling minutes
Step-by-step explanation:
17 + .11x = 22 + .07x
.04x = 5
x = 5/.04 = 125 minutes, is the number of minutes the two plans cost the same
17 + .11*125 = $30.75 is the cost when the two plans cost the same
