What is the mistake in this equation?

2 - 5 = 7

i am giving away a free 50 points for a yt video and this is like the most simple answer. if you can tell me the mistake, you'll get the 50 points and i'll mark you brainiest.

Aretha wanted to gather data about the cost of local bowling leagues in her area. she plotted the data and determined that the average bowling league costs consist of a one-time registration fee and a monthly fee modeled by the equation y = 15x + 20. identify and interpret the y-intercept in this model. the y-intercept is 20. this is the cost per month. the y-intercept is 20. this is the cost of registration. the y-intercept is 15. this is the cost of registration. the y-intercept is 15. this is the cost per month.

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).

If two angles of a triangle have equal measures and the third angle measures 90°, what are the angle measures of the triangle? a. 60°, 60°, 60° b. 45°, 90°, 90° c. 30°, 30°, 90° d. 45°, 45°, 90°