Question

Help please

Answer 1

An easy way to do it is subtituet (-7,5) and (-4,1) into the equations and find out which ones check. remember (x,y)

so A
if we try (-7,5)
5-7=-3/4(-7+5)
we can immediately see that -2 is not equal to -3/4(-2)
so A is wrong


B
if we try (-7,5)
5-5=-4/3(-7+7)
0=-4/3(0)
0=0
so B is correct

C
if we try (-7,5)
5+4=-3/4(-7+1)
9=-3/4(-6)
9 is not equal to 18/4
so C is wrong

D
if we try (-7,5)
5-1=-4/3(-7+4)
4=-4/3(-3)
4=12/3
4=4
D is correct

If you wanted to try the second point (-4,1) in B and D
B
1-5=-4/3(-4+7)
-4=-4/3(3)
-4=-12/3
4=4
B is still correct

D
1-1=-4/3(-4+4)
0=-4/3(0)
0=0
D is still correct

so the answers are B and D

Answer 2

$General\ equation\ for\ line\ in\ slope\ intercept\ form:\\\\y=ax+b\\\\To\ find\ a\ and\ b\ substitude\ points\ (-7,5)\ (-4,1)\ into\ equation\\\\ \left \{ {{5=-7a+b}\ \ \ \ \atop {1=-4a+b\ |*-1}} \right.\\\\ \left \{ {{5=-7a+b}\ \ \ \ \atop {-1=4a-b}} \right.\\\\ +----\\\\Addition\ method\\\\ 4=-3a\ \ |:(-3)\\\\ a=-\frac{4}{3}\\\\ b=5+7a=5+7*(-\frac{4}{3})=5-\frac{28}{3}=-4\frac{1}{3}\\\ Answer\ y=-\frac{4}{3}x-4\frac{1}{3}\\\\ Checking\ solution:\\ y-5=-\frac{4}{3}(x+7)$$y-5=-\frac{4}{3}x-\frac{28}{3}\\\\ y=-\frac{4}{3}x-\frac{28}{3}+5\\\\ y=-\frac{4}{3}x-4\frac{1}{3}\\\\Answer:B \ and\ D.$