Answer:
10:1
Step-by-step explanation:
Answer:
Step-by-step explanation:
First Question
The top question has 2 solutions because eventually you will have to take the square root of (x - 4)^2. One square root will be plus, and the other minus
(x - 4)^2 - 28 = 8 Add 28 to both sides
(x - 4)^2 -28+28 = 8+28 Collect like terms
(x - 4)^2 = 36 Take the square root.
sqrt( (x - 4)^2 ) = sqrt(36)
x - 4 = +/- 6
=============
x - 4 = + 6
x = 6 + 4
x = 10
============
x - 4 = - 6
x = - 6 + 4
x = - 2
The two solutions are (10,0) and (-2,0)
Second Question
The question is solved correctly up to the point where the square root needs to be taken. It is incorrect at that point.
x^2 - 6x - 7 = 0 Add 7 to both sides.
x^2 - 6x = 7 Add 1/2 the linear term and square it to both sides.
x^2 - 6x + (6/2)^2 = 7 + (6/2)^2 Expand the right
x^2 - 6x + 3^2 = 7 + 9
x^2 - 6x + 9 = 16 express the square on the left
(x - 3)^2 = 16 Take the sqrt of both sides.
x - 3 = sqrt(16)
x - 3 = +/-4
============
x - 3 = 4
x = 4 + 3
x = 7
===========
x -3 = - 4
x = - 4 + 3
x = - 1
==========
Solutions
(7,0) and (-1,0)
<h2>
y = 4x - 4</h2>
y = mx + c
First find the gradient.
6 - 2 = 4
Your gradient, m, is 4x.
Now find the constant, c.
y = mx + c
<u>if y = 4 and x = 2</u>
<u />
4 = 4 * 2 + c
4 = 8 + c
4 = 8 - 4
c = -4
<h2>
y = 4x - 4</h2><h2>
</h2>
You can check it's right by substituting the other values.
y = 4x - 4
E.G
36 = 4 * 10 - 4
36 = 40 - 4
21 feet requires = 7 seconds
1 feet requires = 7/21 seconds
180 feet requires
= (7/21)*180
= (1/3)*180
=60 seconds
= 1 minute
Answer:
7.75
Step-by-step explanation:
7.5+8=15.5
15.5/2=7.75