The equation (form) is: 
The solution of the equation is: 
Explanation:
First, let's call the number we are going to solve for "x".
Then two thirds of this number can be written as:

Then "plus 4" means add 4 we get:

"is 7" means that the above expression is equal to 7 (as follows):

The solution of the above equation is:

(x-9) (x+2)=x²+2x-9x-18=x²-7x-18
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)
Answer:
1.6 , 1.6
Step-by-step explanation:
Rounding 1.59 to 1 decimal place, it will be 1.6
1.58, rounded to 1 decimal place is 1.6