Answer:
81
Step-by-step explanation:
Given total number of tests are 5
The grades earned by the students in the tests are 84 , 75 , 97 , 89
let the grade earned by the student in the fifth test be x.
Average=
The condition recquired is Average≥85
≥85
≥85
x≥81.
The least grade the student can earn in the last test so that average is not less than 85 is 81
x²-6x =7
First we have get rid of that 7 from the right side and move it to the left side. To move 7 to the left side, we have to subtract 7 from both sides.
x²-6x-7= 7-7
x²-6x-7 = 0
To make this equation a perfect square, first we have to check the x term. Here -6x given. We have to divide the co-efficient of x by 2, and then we have to add the square of it.
The co-efficient of x is -6 here. Dividing it by 2, we will get -6/2 = -3.
We will have to add (-3)² here. (-3)² is 9. So in the place of -7, we have to make 9, to make the equation a perfect square.
9-(-7) = 9+7 = 16
So by adding 16 to the left side, we can make the equation a perfect square.
x²-6x-7+16 =0
x²-6x+9 =0
x²-6x+(-3)² =0
(x-3)² =0
<span>We move all terms to the left:
-840-(-15(-7x+7))=0
</span>We calculate terms in parentheses: -(-15(-7x+7)), so:
-15(-7x+7)
We multiply parentheses
105x-105
Back to the equation:
<span>
-(105x-105)
</span>
<span>We get rid of parentheses
-105x+105-840=0
We add all the numbers together, and all the variables
-105x-735=0
We move all terms containing x to the left, all other terms to the right
-105x=735
x=735/-105
x=-7
</span>
Answer:
yes it is
Step-by-step explanation:
Answer:
w = 12.38
Step-by-step explanation:
w - 2.58 = 9.8
add 2.58 to both sides
w = 12.38
