Answer:
-5x=-50
x=-10
Step-by-step explanation:
Let's use a for number of days when he shot 50 shots and b for number of days when he shot 100 shots.
We have:
a + b = 20
We also know that he shot total of 1250 shots:
50a + 100 b = 1250
We have two equations. We can solve them for a and b. Let's rearange first equation for a:
a= 20 - b
We insert this into second equation:
50 * (20 - b ) + 100b = 1250
1000 - 50b + 100b = 1250
50b = 250
b = 5
a = 20 - 5
a = 15
Mark shot 100 shots on 5 days.
Answer:
x² + 18x +81
x² - 14x +49
4x²- 4x - 1
Step-by-step explanation:
multiply the x in the first parentheses by x and 9 in the other parentheses and
multiply the 9 in the first parentheses by x and 9 in the other parentheses and add all together
(x+9)(x+9)
x² + 9x + 9x + 81
x² + 18x +81
multiply the x in the first parentheses by x and -7 in the other parentheses and multiply the -7 in the first parentheses by x and -7 in the other parentheses and add all together
(x-7)(x-7)
x² -7x - 7x +49
x² - 14x +49
(2x-1)² is the same as (2x-1)(2x-1)
multiply the 2x in the first parentheses by 2x and -1 in the other parentheses and multiply the -1 in the first parentheses by 2x and -1 in the other parentheses and add all together
(2x-1)(2x-1)
4x²-2x-2x+1
4x²- 4x - 1
