Answer:
Step-by-step explanation:
Since the whole right side of that triangle is equal to 28 and the lower portion is 21, then we know the upper portion is 7. Set up a proportion using those sides and the fact that the 2 triangles are similar:
and cross multiply to get
21x = 126 and
x = 6
-x - y = 8
2x - y = -1
Ok, we are going to solve this in 2 parts. First we have to solve for one of the variables in one of the equation in terms of the other variable. I like to take the easiest equation first and try to avoid fractions, so let's use the first equation and solve for x.
-x - y = 8 add y to each side
-x = 8 + y divide by -1
x = -8 - y
So now we have a value for x in terms of y that we can use to substitute into the other equation. In the other equation we are going to put -8 - y in place of the x.
2x - y = -1
2(-8 - y) - y = -1 multiply the 2 through the parentheses
-16 - 2y - y = -1 combine like terms
-16 - 3y = -1 add 16 to both sides
-3y = 15 divide each side by -3
y = -5
Now we have a value for y. We need to plug it into either of the original equations then solve for x. I usually choose the most simple equation.
-x - y = 8
-x - (-5) = 8 multiply -1 through the parentheses
-x + 5 = 8 subtract 5 from each side
-x = 3 divide each side by -1
x = -3
So our solution set is
(-3, -5)
That is the point on the grid where the 2 equations are equal, so that is the place where they intersect.
Answer:
here is what i found also you could of looked it up
Step-by-step explanation:
(x,y)→(x+4,y)
Sec^2 x - 1 = tan^2x
Proof:
Sec^2x = 1+ tan^2x
1/cos^2x = 1 + sin^2x/cos^2x
<span>1/cos^2x - sin^2x/cos^2x = 1
</span>Using common denominator:
(1-sin^2x)/cos^2x = 1
sin^2x + cos^2 x = 1
cos^2 x = 1 - sin^2x
Substituting :
cos^2x/<span>cos^2x = 1
</span>1 = 1
Left hand side = right hand side
