Solve 7x+3y=8 and 4x-y=-9 simultaneously

x = -1 and y = 5

Step-by-step explanation:

7x + 3y = 8 equation 1

4x - y = - 9 equation 2

Solving the simultaneous linear equation by substitution method , make y the subject of the formula from equation 2 , we have

y = 4x + 9 equation 3

substitute y = 4x + 9 into equation 1 , we have;

7x + 3 ( 4x + 9 ) = 8

7x + 12x + 27 = 8

19x + 27 = 8

subtract 27 from both sides

19x = -19

divide through by 19

x = -1

substitute x = -1 into equation 3 , we have

y = 4 ( -1) + 9

y = -4 + 9

y = 5

Therefore :

x = -1 and y = 5

-3

step-by-step explanation:

a drawing really does here:

so i draw the horizontal line y=2 and the vertical line x=-2 at this intersection i put b (this is where my right angle is going to be).   so point b is at (-2,2).   point a is 5 units long and is also on y=2 so this point has to be (3,2) or (-7,2) -doesn't matter i will go with (3,2).

now we know c is at (-2,y) we don't know the y yet bet we know that c is on x=-2.

we have the area of the triangle is .5bh=12.5

we know the base length is 5 (ab)

we have the height is (2-y) if you look at your

plug in

.5(5)(2-y)=12.5

solve for y to get the y-coordinate for c

2.5(2-y)=12.5

divide both sides by 2.5 giving:

2-y=5

now subtract 2 on both sides

-y=3

y=-3