There are 2 terms. Keep them separate until the last step.
Start calculating in the innermost bracket
#color(blue)(10)- [ 50\div ( color(red)(- 2\cdot 25)) - 7] \cdot 2^ { 2}" "larr color(red)(-2xx25 =-50)#
=#color(blue)(10)- [ color(red)(50\div (- 50)) - 7] \cdot 2^ { 2}" "larrcolor(red)(50div-50 =-1)#
=#color(blue)(10)- [ color(red)(-1 - 7)]xx 2^2" "larr color(red)(-1-7 =-8)#
=#color(blue)(10)- [ color(red)(-8xx 4)])color(white)(xxxxxxx.xxxx) "larr color(red)(-8xx4=-32#
=#color(blue)(10)- [ color(red)(-32)]color(white)(xxxxxxxxxxxxxx) "larr color(red)(-(-32) = +32#
=#color(blue)(10)color(red)(+32)#
=#42#