Answer:-2.3
Step-by-step explanation:
___-1=10-3
x-1=10-3
x-1=7
x=8
therefore the blank is 8
B. is the correct answer you got it right
Malory your fellow helper
we know the perimeter is 24, and is an equilateral triangle, so it has three equal sides, so each side is 24 ÷ 3 = 8.

X+y+5=0
y=-x-5
If a solution exists y=y so we can say
x^2-9x+10=-x-5 add x+5 to both sides
x^2-8x+15=0 now factor
x^2-3x-5x+15=0
x(x-3)-5(x-3)
(x-5)(x-3) so x=3 and 5, using y=-x-5
y(3)=-8 and y(5)=-10
So the two solutions are:
(3,-8) and (5,-10)