The sequence of letters in a congruence statement is important: it tells you the corresponding parts.
A triangle, such as ΔCAT, is named using the names of its vertex points. When it is said to be congruent to ΔDOG, it means these correspondences (and congruences) exist:
angle C to angle D . . . . . first letters correspond
angle A to angle O . . . . . second letters correspond
angle T to angle G . . . . . third letters correspond
segment CA to segment DO . . . . . named by 1st & 2nd letters
segment AT to segment OG . . . . . named by 2nd & 3rd letters
segment CT to segment DG . . . . . named by 1st & 3rd letters
Only one of these is on your list of answer choices:
x^2+3x+4-x=7 x^2+2x+4=7 (factor) x^2+2x-3=0 (x+3)(x-1)=0 X= -3 and X=1 (Plug x in for y) Y= 1^2+3(1)+4 Y=8 (Check your answer on the second equation) 8-1=7 7=7 (Which is the solution)